Category Archives: OUTBREAK REPORT

Occurrence of cholera in Lukanga fishing camp, Kapiri-mposhi district, Zambia

R Murebwa-Chirambo1, R Mwanza2, C Mwinuna3, ML Mazaba1, I Mweene-Ndumba1, J Mufunda1
  1. World Health Organization, Country office, Lusaka, Zambia
  2. Ministry of Health, Provincial Health Office, Kabwe, Zambia
  3. Ministry of Health, District Health Office, Kapiri Mposhi, Zambia

Correspondence: Rufaro Murembwa-Chirambo (murembwar@who.int)

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Murebwa-Chirambo R, Mwanza R, Mwinuna C, Mazaba ML, Mweene-Ndumba I, Mufunda J. Occurrence of cholera in Lukanga fishing camp, Kapiri-mposhi district, Zambia. Health Press Zambia Bull. 2017;1(1) pp56-62

Most of the cholera outbreaks in Zambia have been recorded from fishing camps and peri-urban areas of the Copperbelt, Luapula and Lusaka provinces. Cholera cases have been recorded every year in the Lukanga fishing camps in the last five years. This article documents a cholera outbreak reported at the Lukanga fishing camp in Kapiri Mposhi district in September, 2016. All cases that met the cholera case definition as prescribed in the Integrated Diseases Surveillance and Response guidelines were admitted and treated using WHO standard protocols. A total of 27 patients all adult except 1, 26 of whom were male were seen at the cholera treatment center. Two facility deaths were recorded during the outbreak. All cases were linked to the fishing camps, lack of clean drinking water and poor sanitary conditions among other factors. The incubation period was about 4 days. All patients responded well to treatment with doxycycline and intravenous fluids. There were 2 facility deaths recorded; Case Fatality Rate (CFR): 7.4%. All cases tested on RDT and the water samples were positive for cholera. The outbreak on the Lukanga swamps is associated with choleravibrio. There is need to employ interventions in the area of water and sanitation on the Lukanga swamps in order to address the annual cholera outbreaks.


Introduction

The first outbreak of cholera in Zambia was reported in 1977/1978, then cases appeared again in 1982/1983. The first major outbreak occurred in 1990 and lasted until 1993. Since then, cholera cases were registered every year except in 1994 and 1995[1]. A suspected cholera outbreak was reported at the Lukanga swamps / fishing camp in Kapiri Mposhi district in September, 2016.

Kapiri Mposhi district is situated about 180 km from Lusaka and 50km from Kabwe towns and lies along the Great-North road. It has 30 health facilities, managing a total population of 282,308. The Lukanga swamps are located 70km North West of Kabwe and 130km from Kapiri Mposhi District. The Lukanga swamps are shared among the four districts of Central Province namely, Kabwe, Mumbwa, Ngabwe, Chisamba and KapiriMposhi. The swamps are easily accessible through Kabwe and fall within the Waya health centre catchment area of Kapiri Mposhi district. Waya health centre has a catchment population of 16,000 and 5000 living on the upper land and the Lukanga swamps respectively (CSO, 2010).

Cholera is an acute secretory watery diarrhoea caused by the Gram-negative bacterium Vibrio cholerae, with 01 and 0139 types being the principal ones associated with epidemics and they thrive wherever crowded housing conditions exist and water and sanitary conditions are suboptimal [2,3,4,5].

It’s transmitted by the fecal oral route. The organism produces an enterotoxin, promoting secretion of fluids and electrolytes into the lumen of the small intestine. Cholera epidemics have been increasing in intensity, duration, and frequency, showing the need for more effective approaches to prevention and control [6, 7].

Although most cholera infections are not detected, large cholera outbreaks, such as those seen in Haiti [6] Viet Nam [7] and Zimbabwe [8] in recent years, can occur. Industrialized countries have seen practically no cholera cases for over a century because of their good water and sewage treatment infrastructure, though it remains the significant cause of illness and death in many

African countries. The priority in management of any watery diarrhoea is replacing the lost fluid and electrolytes and providing an antimicrobial agent when indicated. Although the disease may be asymptomatic or mild, severe cholera can cause dehydration and death within hours of onset. Mortality is higher in pregnant women and children [7].

Mortality rates are lowest where intravenous therapy is available [9]. In the twenty-first century, sub-Saharan Africa bears the brunt of global cholera, with a high mortality rate [10]. Improving global access to Water, Sanitation and Hygiene (WASH), as well as cholera treatment is a critical step to reducing Africa’s cholera burden [11]. The disease burden in most outbreaks is underreported. Fear of travel-related and trade-related sanctions may contribute to underreporting and may jeopardize efficiency of control measures [12]. Limitations in surveillance systems, inconsistencies in case definitions, variation in modalities, lack of standard terminology, completeness and lack of laboratory diagnostic capacities may also contribute to under- as well as overreporting[13, 14]. Most of the cholera outbreaks in Zambia in the past have been recorded from fishing camps and peri-urban areas of the Copperbelt, Luapula and Lusaka provinces. The article documents the epidemiological findings of the 2016 cholera epidemic within the Lukanga swamps in Kapiri-Mposhi district.

Methods

After having recorded several cases with diarrhoea and vomiting from the fishing camp, a suspicion of cholera was raised, followed by establishment of a Cholera Treatment Centre (CTC), 100 meters away, from Waya health centre.

Case investigation: All suspected cases were admitted and managed and the Cholera Treatment Centre. A suspected case of cholera was defined as any person admitted to the cholera treatment centre with acute watery diarrhoea, with or without vomiting. The demographics and clinical history on every suspected case were documented including age, sex, residency and symptoms.

Laboratory investigation: On admission, Rapid Diagnostic Tests (RDT) using SD Bioline-Cholera Ag 01/01/39 for cholera were conducted for all suspected cases.

Water sampling was also performed.

Case management: WHO cholera treatment protocols were implemented on all patients. Infection control was a top priority using disinfectants chlorine. All patients were treated with doxycycline, metronidazole and intravenous fluids.

Data analysis: Data on the progress of in patients and new admissions were sent 2 to 3 times daily to the Ministry of Health, WHO and other partners. A line list was compiled daily to keep track of new admissions. A descriptive analysis of the outbreak and review of literature was used to determine the extent and factors contributing to the epidemic.

Results

A total of 27 cases were seen at the cholera treatment centre from 13 different lagoons, with majority coming from Namabala lagoon 5/27. There were two facility deaths recorded; case ratality rate (CFR): 7.4%. All patients except one were male. Except for one 15 year old male, the rest were adults. The incubation period was about 4 days. There were 5 additional cases reported from Kapiri Mposhi urban, 3 from Kabwe and 1 from Chibombo districts, all linked to have had visited the Lukanga swamps or received visitors from there. The index case was reported on 11th September, 2016 and the last case on the 21st October, 2016, as shown in figure 1.

Figure 1 Cholera incidence in Lukanga swamps, September, 2016

Laboratory results

Laboratory investigations for stool culture with TCB media revealed growth of Vibrio Cholerae on all the 10 samples tested confirming cholera. The sensitivity test results also revealed that the species organism was sensitive to doxycycline. The 22 samples tested using RDT were also positive. All water samples collected were positive for the cholera vibrio.

Three water samples from selected lagoons were tested and were all positive for Vibrio cholerae. In addition, 14 RDTs were done on the water samples using Hydrogen Sulphide tests and they all showed heavy coliform contamination demonstrating the poor sanitary conditions.

Environmental findings

Environmental surveillance revealed non-availability of sanitation and clean drinking water infrastructure on the swamps being factors that precipitated the outbreak. The persons affected, most of whom are fishermen have no access to sanitary facilities and safe drinking water. They use the swamp waters for all need including drinking and sanitation.

Discussion

The outbreak that occurred in Kapiri Mposhi, in particular on the Lukanga swamps is linked to infection with Vibrio Cholerae as per laboratory confirmation. Close to 30 persons on the swamps were affected. Considering all those affected lived on the swamps which have no prescribed sanitation or clean water source, it can be assumed that the source of infection was the contaminated water from the swamps. There was evidence of water contamination with Vibrio cholerae. Other persons outside the swamps from Kapiri-Mposhi urban, Kabwe and Chibmbo districts which are in close proximity to the swamps who were exposed on visiting the swamp or in contact with persons from the swamps were affected.

There were two facility deaths recorded (CFR = 7.7%). WHO indicates CFRs up to 20% in rural areas. It is also possible that the denominator (cases investigated) is lower than the actual number of cases and so increasing the CFR. The actual number of deaths is smaller than in previous outbreaks and this could be attributed to high community sensitization, which prompted patients to seek treatment at the cholera center timely. The 2015 outbreak recorded 5 deaths [15]. Good case management of cases could have also led to adequately managing the cases. However, many deaths due to cholera have been reported from other places, including the same Lukanga swamps More than 40 years after its resurgence in Africa in 1970, cholera remains a grave public health problem, characterized by large disease burden, frequent outbreaks, persistent endemicity, and high Case Fatality Rates (CFR) [16]. Population density, poor sanitation and health infrastructure, and logistical obstacles to appropriate case management also contribute to a high case-fatality rate in epidemic settings [17]. Of the estimated 3 to 5 million cases that occur globally every year, about 100 000 to 120 000 die [18].

Analysis of reports from previous outbreaks indicate that cholera epidemics in Lukanga swamps occur in the dry season, just before the onset of the rains. The waters in the swamps are low and so the flow of water is poor. The cholera outbreak showed two peaks, with an initial sharp rise at the beginning of September, and the second peak occurred around mid-October within the hot dry season in Zambia which spans from September to November. Fishermen and their families usually spend several weeks every year in fishing camps, in which the swamps is the only source of water. Interventions prescribed such as boiling water are not adhered to due to lack of resources such as firewood, charcoal let alone electricity. Chlorinating water is also prescribed but most persons do not have resources to purchase it. Although chlorine was distributed within the population, it appears there was a shift of source of infection each time the people were provided with clean drinking water (through distribution of liquid chlorine), with people in other lagoons that did not have access to chlorinated water being exposed. It may have been more effective if distribution was done in all lagoons within the same period of time. This way, re-emergence of cholera cases from other sources would be reduced.

There is poor sanitation and clean drinking water infrastructures are likely the contributing factor to the continued outbreaks on the Lukanga swamps. The findings of this study show that there were poor sanitary conditions in the fishing camps, where the same water is used for drinking and all sanitary purposes. There is need to come up with ways of improving the sanitary conditions in the swamps or consider closing all fishing activities until a solution is sanitary conditions improve. Many countries are making important efforts to contain the spread of cholera, but concerns have been raised about the growing number of people living in unsanitary conditions who are at risk for outbreaks of cholera and other epidemic-prone diarrheal diseases [18].

The Lukanga swamps is one of the areas that was considered for cholera vaccination due to cholera endemicity. The first round of Oral Cholera Vaccine (OCV) was conducted from 28th October to 5th November 2016, while the second round was conducted from 26th to 30th November 2016. The target population was from 1year of age upwards, targeting 5,000 people living in Waya catchment area. WHO recommends instituting cholera immunization, in conjunction with other prevention and control strategies, in endemic areas, and perhaps in areas at risk for cholera outbreaks [5, 6]. In 2011, the 64th World Health Assembly adopted resolution WHA 64.15 recognizing the re-emergence of cholera as a significant public health burden and calling for the implementation of an integrated and comprehensive approach to cholera control [4, 7]. Local capacities for improving diagnosis, and for collecting, compiling and analysing data, need to be strengthened so that vulnerable populations living in high-risk areas may be identified and benefit from comprehensive control activities. This includes provision of safe water to all African populations. This requires considerable human and financial resources and time [4]. Prevention, preparedness and response all depend upon effective surveillance system and are linked and interdependent. There is a need to shift the emphasis from response to prevention in order to avert outbreaks in the fishing camps by providing safe water and means for disposal of human excreta and by working with communities to encourage behavioral change to diminish the risks of infection [19].

Acknowledgements

The Provincial Medical Office and District Medical Office Surveillance staff and staff at Waya health centre, for their hard work in the response of the outbreak. Not forgetting the other district and provincial staff for the support and involvement.

References

 

  1. World Health Organization. Global task force on cholera control: cholera country profile: Zambia, 2011.
  2. Morris JG Jr. Cholera and other types of vibriosis: a story of human pandemics and oysters on the half shell. Clin Infect Dis. 2003; 37: 272–280
  3. Greenough WB III. The human, societal, and scientific legacy of cholera. J Clin Invest. 2004; 113: 334–339
  4. Nelson EJ, Harris JB, Morris J G Jr, Calderwood SB and Camilli A. Cholera transmission: the host, pathogen and bacteriophage dynamic. Nat Rev Microbiol. 2009; 7: 693–702
  5. World Health Organization. Cholera vaccines: WHO position paper. Wkly Epidemiol Rec. 2010; 85: 117–128
  6.  Chao DL, Halloran ME, Longini, IM. Vaccination strategies for epidemic cholera in Haiti with implications for the developing world. Proc Natl Acad Sci USA 2011; 108: 7081-5
  7. World Health Organization. Outbreak news – severe acute watery diarrhoea with cases positive for Vibrio cholerae, Viet Nam. Wkly Epidemiol Rec 2008; 83: 157-8
  8.  Zimbabwe: OCHA Cholera Update Situation Report No. 22, New York: United Nations Office for the Coordination of Human Affairs; 2012.
  9. Centers for Disease Control and Prevention. Cholera, 2011.
  10. Gaffga NH, Tauxe RV, Mintz ED. Cholera: a new homeland in Africa? Am J Trop Med   Hyg. 2007;77: 705-13.
  11. World Health Organization. Cholera 2011. Wkly Epidemiol Rec. 2012; 87: 289–304.
  12. World Health Organization. Addressing sex and gender in epidemic­prone infectious Diseases. Unpublished manuscript, Geneva, 2007.
  13. Kenneth Todar. Todar’s Online Textbook of Bacteriology, 2010.
  14. Ali M, Lopez A, You Y Kim, Y Sah B, Maskery B, Clemens J. The global burden of cholera. Bull World Health Organ. 2012; 90: 209-18.
  15. Provincial Medical Office Reports to the Ministry of Health. Unpublished report. 2015
  16. CDC, Dynamics of Cholera Outbreaks in Great Lakes Region of Africa, 1978–2008, Volume 17, Number 11—November 2011.
  17. Birmingham ME, Lee L, Ndayimirije N, Nkurikiye S, Hersh B, Wells J. Epidemic cholera in Burundi: patterns of transmission in the Great Rift Valley Lake region. Lancet. 1997;349:981–5.
  18. Shapiro RL, Otieno M, Adcock P, Phillips-Howard P, Hawley W, Kumar L. Transmission of epidemic Vibrio cholerae O1 in rural western Kenya associated with drinking water from Lake Victoria: an environmental reservoir for cholera? Am J Trop Med Hyg. 1999;60:271–6.
  19. Bompangue D, Giraudoux P, Handschumacher P, Piarroux M, Sudre B, Ekwanzala M. Lakes as source of cholera outbreaks, Democratic Republic of Congo. Emerg Infect Dis. 2008; 14: 798–800

 

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Outbreak of Anthrax among humans and cattle in Western province of Zambia, November 2016 to January 2017

N Kasese-Chanda1, B Mulubwe1, F Mwale1

  1. Ministry of Health, Directorate of Public health, Lusaka, Zambia

Correspondence: Nancy Kasese-Chanda (kasesechanda@gmail.com)

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Kasese-Chanda N, Mulubwe B, Mwale F. Outbreak of Anthrax among humans and cattle in Western province of Zambia, November 2016 to January 2017. Health Press Zambia Bull. 2017;1(1), pp50-55

An outbreak of anthrax occurred in Western province on 11th November 2016. The outbreak was confirmed using PCR.  Out of the 7 specimens examined for Bacillus anthracis, 3 were positive.  Altogether 67 suspected cases were investigated out of which one death (1.5%) was reported.  Over half of the cases were of age 15 years or older (56.1%) and males (56.7%).  Four peaks were identified on the epidemiologic curve suggesting multiple sources of infection.  Factors associated with the outbreak included: animal movement, belief that all the dead animals have to be eaten ‘there is no grave for animals’ and animals on loan (mafisa) cannot be disposed of without owners’ approval, hunger land low levels of animal vaccination coverage.  In conclusion, disposal of carcasses should be done by burning and burying followed by decontamination. Certificates should be issued to show that disposal was conducted by government.  Anthrax vaccines should be given to farmers free of charge through Ministry of Livestock and Fisheries.


Introduction

Outbreaks of anthrax have been documented in Zambia affecting humans as well as wild and domestic animals. The disease, caused by Bacillus anthracis, has been reported in wildlife such as hippo and buffalo and among cattle [1,2]. There are three types of anthrax in humans: cutaneous, gastrointestinal, and pulmonary: cutaneous being the most common form. Humans generally acquire the disease from infected animals as a result of handling the animal carcass or ingestion of its meat. Anthrax is not known to be transmitted from person to person [3]. It continues to be reported from many countries in domesticated and wild herbivores, especially where livestock vaccination programmes are inadequate or have been disrupted [4].

Anthrax outbreaks continue to occur globally, more commonly in sub-Saharan Africa, Asia and Central and South America [4]. Zambia has experienced more recently in 2016 two anthrax outbreaks affecting humans and animals in Muchinga and Western provinces [2,5]. The objectives for the current outbreak investigation were to assess: the extent of the outbreak; effectiveness of the interventions in mitigating the outbreak; and determine the needs required to mitigate the outbreak effectively and efficiently.  

Methods

The investigation was conducted in Western Province, one of the 10 provinces of Zambia, is located 22 degrees and 25.30 degrees east and 13.45 degrees and 17.45 degrees south. It has an area of 126 386-sq kilometres (16.8% of the total land of Zambia). It has 16 districts, five of which share an international boundary with Angola, while two districts share a boundary with Namibia. The poverty level in the province is at 80.4% (LCMS 2010). The province has varied communication challenges, with limited phone facilities in health centres, and poor road network posing limited abilities in referrals and challenges.  The outbreak occurred in four districts of the Western province: Shang’ombo, Nalolo, Limulunga and Kalabo (Figure 1).

 Figure 1 District with suspected anthrax cases in Western province

According to International Strategy for Disaster Reduction ISDR technical Guidelines of Zambia, anthrax is a notifiable disease with one case constituting an outbreak. WHO and CDC [6] defined a suspected case of anthrax as any person with acute onset characterized by several clinical forms that are:  (a)  cutaneous form: any person with skin lesion evolving over 1 to 6 days from a papular through a vesicular stage, to a depressed black eschar invariably accompanied by oedema that may be mild to extensive ; or (b)  gastro-intestinal: any person with abdominal distress characterized by nausea, vomiting, anorexia and followed by fever; or (c)  pulmonary (inhalation): any person with brief prodrome resembling acute viral respiratory illness, followed by rapid onset of hypoxia, dyspnea and high temperature, with X-ray evidence of mediastinal widening ; and has eaten and / or handled meat of a suspected or known confirmed case of anthrax in a human was defined as a clinically compatible case of cutaneous, inhalational or gastrointestinal illness that is laboratory-confirmed by isolation of B. anthracis from an affected tissue or site; or other laboratory evidence of B. anthracis infection.

Data were collected using data reviews, interviews, meetings with various stakeholders and field visitations. Case records from health facilities were reviewed age, sex, physical address and day of onset. Various stakeholders including health facility staff, veterinary assistants, agricultural field officers and community health committee members were interviewed. Meetings were also held with the district commissioners, district health officers, veterinary officers at the district and provincial level.  The University of Zambia School of Veterinary Medicine confirmed the presence of Bacillus anthracis by Polymerase chain reaction (PCR).

Results

The outbreak was first reported on 11th November, 2016 with the index case being a male farmer, from Shang’ombo, Western province.  Altogether 67 cumulative cases as at 19th January 2017 were investigated with Kalabo reporting most of the cases (31). Overall, one death (1.5%) was reported.  In Kalabo, the estimate case fatality rate during the period 11th November to 19th January was 3.2% among 31 suspected cases.  Table 1 shows the distribution of suspected cases of anthrax by district as at 19th January 2017.

Figure 2 shows an Epi-curve for the 4 districts affected by anthrax 11-November 2016 – 19 January 2017. There are four peaks: one between 27-30 November 2016, one on 22nd December 2016, another one between 29 December 2016 and 1st January 2017 and the last one on 9th January 2017.

Figure 2 Epi-curve for the 4 districts affected by anthrax 11-November 2016 – 19 January 2017

The distributions of suspected anthrax cases by age, sex and district are shown in Table 2.  Over half of the cases were of age 15 years or older (56.1%) and males (56.7%).  These findings are shown in Table 2. Out of the 7 specimens examined for Bacillus anthracis, 3 were positive.

Factors associated with anthrax

The following were factors hypothesized to be contributing to the continued spread of the disease: (a) Animal movement: (b) Disposal of dead animals: (c) Poverty: (d) Lack of vaccination:  

Discussion

The current anthrax outbreak in Western province was confirmed using PCR.  The epidemiologic curve suggests an active transmission of the disease throughout the period with multiple sources of infection.  Persons most affected were of age 15 years or older and were males.  The risk group for acquiring anthrax of skinning and butchering cattle that could have died of anthrax are usually older males.  On a smaller scale, this subpopulation of inhabitants of Western province is also involved in tanning the cattle hides and making stools and mats using them. While, health education intervention should be implemented to the entire population, older men should also be specifically targeted in order to curtail anthrax epidemics should they occur in Western Province.  Women may have been infected whilst preparing infected meat for drying or cooking.  Meanwhile, the younger age groups could have been infected by eating under-cooked infected meat.
In conclusion, disposal of carcases should be done by burning and burying followed by decontamination. Loaning of animals presented a problem of disposal as owners were not available.  Issuing of certificates should be made to show that disposal was conducted by government.  Anthrax vaccines should be given to farmers free of charge through Ministry of Livestock and Fisheries.The outbreak of anthrax in Western Province has persisted despite community sensitization messages in an area endemic for anthrax where the community should know better, suggesting need for targeted interventions. The results presented are limited in that both bivariate and multivariate analysis of risk factors associated with anthrax cases was not done. However, we hypothesize that animal movement, disposal of dead animals, poverty and lack of vaccination in cattle are factors all associated with the occurrence of anthrax outbreak in the affected districts. There is an animal transportation corridor from Shangombo to Mongu as a result pasture contamination is possible as animals move from one place to the other. The community hold a belief that all the dead animals have to be eaten ‘there is no grave for animals’ and animals on loan (mafisa) cannot be disposed of without owners’ approval. Additionally, an agriculture officer reported that mainly people are eating mango mixed with some mealie meal. Relish is rarely found and this could be one reason why they are opting to eat risk meat from diseased animals. Finally, less than 5% of cattle are vaccinated against anthrax in the Province. Anthrax is still classified as a management disease and therefore it is the owner of animals who is to ensure that animals are vaccinated. This has proved not effective as seen from the coverage of vaccinated animals even though the cost of vaccination is as low as K2 ($0.2) per animal.

Acknowledgments

We thank the following who responded to our questions and provided information in this report: Western PHO, Kalabo DHO, Limulunga DHO, Numa RHC staff and Community members in the affected districts.   

References

1.MOH. Mission report on technical support for anthrax outbreak in Chama district, Eastern province. Unpublished report submitted to the Ministry of Health, Lusaka, Zambia, 2011.

2.MOH Directorate of Public health. Anthrax outbreak in Muchinga. Unpublished report submitted to the Ministry of Health, Lusaka, Zambia, 2016.  

3.CDC. Anthrax (Bacillus anthracis) 2010 Case Definition. URL: https://wwwn.cdc.gov/nndss/conditions/anthrax/casedefinition/2010/

4.World Organization for Animal Health, World Health Organization, Food and Agriculture Organization of the United Nations. Anthrax in humans and animals. 4th edition. World Health Organization, 2008. URL: http://www.who.int/csr/resources/publications/anthrax_w eb.pdf.

5.Herriman R. Anthrax outbreak linked to tainted hippo meat more than doubles in Zambia. URL: http://outbreaknewstoday.com/anthrax-outbreak-linkedto-tainted-hippo-meat-more-than-doubles-in-zambia26869/.

6.IDSR technical Guidelines Zambia. Lusaka: Ministry of Health, 2011.

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Cutaneous Anthrax outbreak in Chama District, Muchinga province, Zambia, 2016 as history repeats itself

P Mwambi1, J Mufunda1, P Mwaba2, N Kasese-Chanda2, CM Mumba2, T Kalumbi2,  M Chaula2, N Mweemba1, MB Hang’ombe3, H Higashi4, R Akamatsu4, ML Mazaba1,5
1.World Health Organization, Lusaka, Zambia
2.Ministry of Health, Lusaka, Zambia
3.Center for Zoonoses Control, University of Zambia, Lusaka, Zambia
4.Hokkaido University Research Center for Zoonosis Control, Global COE Program,Kita-ku, Sapporo, Japan
5.University Teaching Hospital, Lusaka, Zambia
Correspondence: Patricia Mwambi (mwambip@who.int)

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Mwambi PEM, Mufunda J, Mwaba P, Kasese-Chanda N, Mumba CM, Kalumbi T, et al. Cutaneous Anthrax outbreak in Chama District, Muchinga province, Zambia, 2016 as history repeats itself. Health Press Zambia Bull. 2017;1(1) pp38-49

An outbreak of anthrax has been confirmed in Chama district in Zambia affecting close to 80 persons. A previous outbreak in the same area was confirmed in 2011 with 521 humans affected and 6 human and over 80 hippos dead. To understand the disease situation and provide technical support the Ministry of Health in collaboration with the World Health Organization (WHO) in Zambia and Center for Zoonoses control University of Zambia investigated the outbreak in various villages. The index case, a 22-year-old male presented at Pondo rural health centre with eschar invariably accompanied by oedema on the cheek with onset 22nd September 2016. More patients mostly below 20 years of age from five RHCs were seen thereafter with varied lesions papules, vesicles and eschars and treated with ciprofloxacin. Most patients were associated with eating hippo meat. Various interventions were put in place to control the outbreak including case detection, case management, contact tracing and community awareness. Field investigations observed dead carcasses of Hippo and Buffalo. Bacillus anthracis was isolated from humans, buffalo, hippo and the environment confirming the outbreak link to Anthrax infection suggesting the need to strengthen surveillance, diagnosis, community sensitization and treatment of affected persons for effective disease control. The rapid response by the Ministry of Health, WHO Zambia, Center for Zoonosis Control, and  ZAWA necessitated by the availability of financial resources provided by MOH and WHO Zambia contributed significantly to the timely containment of the outbreak and avoidance of any fatalities.


 

Introduction

Anthrax is a zoonotic disease with its natural reservoirs being hoofed animals that are known to carry the Bacillus anthracis. Most commonly it is found in grazing herbivores such as cattle, sheep, goats, camels, horses, and pigs [1], but has also been associated with transmission from wildlife to humans by various modes, notably buffalo and hippos in Zambia [2,3]. It is a serious bacterial infection caused by Bacillus anthracis that occurs primarily in animals. Cattle, sheep, horses, mules, and some wild animals are highly susceptible [4]. Humans become infected when the spores of Bacillus anthracis enter the body by contact with animals infected with Bacillus anthracis or from contact with contaminated animal products, insect bites, ingestion, or inhalation [5].

The developed world has no or lower incidence of anthrax infection, meanwhile it continues to be a problem of public health concern in the developing world and countries that do not have veterinary public health programs that routinely vaccinate animals against anthrax [6]. Continued outbreaks in areas with previous outbreaks may occur because anthrax spores survive for decades, even under adverse conditions, contaminating the soil [7]. Anthrax infections in humans occur in three forms including cutaneous, gastrointestinal and pulmonary depending on route of exposure, with up to 95 % being cutaneous [8, 9].

Cutaneous infections initially appear as painless, itchy papules on the face, neck, forearms or hands and ulcerate within 7 to 10 days. These subsequently form a black painless eschar. The patient may also incur localised swelling, usually of the face and neck, with painful swollen lymph nodes and systematic symptoms. Literature reveals no human to human spread, no racial, sexual or age association with the disease, although commonly among young and middle ages as it is often related to industrial exposures, way of life and livestock farming [6]. A well managed outbreak with appropriate therapy will reduce and even exclude fatalities.

Zambia has had outbreaks of anthrax in human and animal populations with previous studies showing that clostridia infections and anthrax outbreaks are higher in the Western Province and Luangwa valley than the rest of the country [10-12]. Confirmed outbreaks affecting cattle in Western province from 1989-1995, in which 1,626 suspected cases of anthrax were identified, 51 cases were confirmed with Bacillus anthracis infection. During the 1990 outbreak alone, 220 cases of human anthrax cases and 248 human cases during 1991-1998 were confirmed with 19.1% and 7.7% case fatality rates, respectively [13].

Recurrence of anthrax outbreaks have been linked to various ecological factors such as cycles of heavy rainfall followed by periods of dry weather, high evaporation potential of flood water, the presence of calcareous soils and ambient temperatures above 15.5 degrees [14-16]. The Anthrax spores are very resistant, remaining dormant and viable in nature for >100 years [2]. Chama district recorded an outbreak of anthrax in August 2011 that saw over 80 hippopotamuses die after showing signs of infection with Bacillus anthracis, followed by 521 suspected human cases resulting in six human community deaths associated with Bacillus anthracis infection  and about 80 hippopotamus deaths [3, 17].  Five years later, Muchinga Provincial Medical Office received a report of a suspected anthrax outbreak on 27th September 2016 in the southern part of Chama district, recording up-to 79 human cases and 25 animals including hippos and buffalos by end of October 2016. A quick response team consisting of surveillance officers, epidemiologists, clinicians, laboratory scientists, veterinary staff and health promotion staff from the Ministry of Health, the World Health Organization in Zambia, Center for Zoonoses control University of Zambia, the Ministry of Fisheries and Livestock (MFL) as well as National Parks and Wildlife (NPW) investigated and provided technical support in managing the outbreak

Methods

A descriptive cross sectional study of a recent outbreak in Chama was undertaken. The outbreak response team reviewed case records at the local facilities, undertook field visitations to affected areas and conducted interviews with health providers, NPW staff at the camps, village scouts, individual clients, Community Based Volunteers (CBVs), community leaders, school teachers/pupils and community members and visited the risk areas, that is, Baghdad lagoon on the Luangwa river (GPS coordinates S 1161221, E03268300 and elevation 617), NPW camps and the affected villages in the RHCs catchment areas.

Local health officials in the affected area collected specimens from affected patients which, included swabs from vesicular lesions and blood. The specimens were collected by swabbing of cutaneous lesions from suspected patients. A total of 12 swabs and blood specimens were submitted for anthrax detection and confirmation.

In case of animals, sections of tissues and bones from carcasses were obtained from hippo and buffalo, while soil samples from hippo and buffalo grave sites and soil on land where hippos graze from were obtained. Water samples from the lagoon where hippos were struggling to survive were also collected. The collected samples were carefully transported to the laboratory for analysis.

Cuttings of flesh from the tongue, buccal mucosa and neck area of a Hippo and buffalo, as well as soil samples from hippo grave sites, soil on the land where the hippos died and water samples from Baghdad lagoon were tested for anthrax.

Study area
Chama district is one of the 7 districts in Muchinga Province in the north-eastern part of Zambia. It is a Game Management Area (GMA) and it experiences a lot of human-animal conflicts. Most agricultural activities are undertaken on the plateau while in the valley they heavily depend on wildlife. Chama South, the area affected by the outbreak is predominantly a game reserve with some game camps and lodges for professional hunters and tourists. Cases were recorded in Chigoma, Chikwa, Lundu, Kapichilasenga and Pondo Rural Health Centres (RHCs).

Case definition of Anthrax

  • A suspected case was defined as person with acute onset characterized by several clinical forms that are:
  • Cutaneous form-any person with skin lesion evolving over 1 to 6 days from a papular through a vesicular stage to a black eschar invariably accompanied by oedema that may be mild to extensive;
  • Gastro intestinal-any person with abdominal distress characterised by nausea, vomiting, anorexia and followed by fever;
  • Pulmonary (inhalation anthrax)-any person with a brief prodrome resembling acute viral respiratory illness, followed by rapid onset of hypoxia, dyspnoea and high temperature with x ray evidence of meditational widening.

A confirmed case of anthrax in human can be defined as clinically compatible case of cutaneous, inhalational or gastrointestinal illness that is laboratory confirmed by isolation of Bacillus anthracis from an affected tissue or site [18].

Public Health response
The response to the outbreak included case detection, case management, contact tracing, community sensitizations and stakeholders’ involvement. All cases meeting the case definition were referred to the rural health centres for management as outpatients except for one who was treated as an inpatient for four days because of his presentation with abdominal pains, difficulties in breathing, extensive swelling of the face and head. The patient was discharged in a stable condition. A line list of cases was maintained and updated accordingly.  Active cases were treated with oral ciprofloxacin of varied dosages according to age twice daily for 7 days: below 4 years 125mg; 4 to <15 years 250mg ; ≥ 15 years 500mg. Contacts traced were given a prophylactic stat dosage according to age as above.

Communication on the outbreak was strengthened at all levels and regular briefing reports were made at different levels and appropriate times. The Minister of Health issued a press statement about the outbreak that contributed to raising public awareness of the outbreak and response interventions that were in place. Community sensitization was conducted through the community radio, Zambia News and Information Services public address system, community and school meetings, door to door visitations by community health workers and meetings with different stakeholders and community leaders. Standard messages were developed on the types of anthrax, causes, signs and symptoms, risk factors, prevention, treatment and the importance of early care seeking and were disseminated widely in the community. Another key message given to the community was about the importance of reporting deaths of domestic and wild animals and to avoid getting into contact or eating such animals.

Decontamination using lime was conducted on animal grave sites both on the river banks and other grave site on the land and the bush. All the dead buffaloes and hippos remains were burned and buried on their grave sites. A Mobile Bio-safety level 3 laboratory for quick confirmation of cases both in human and animal populations was put in place.

Laboratory investigations
A biosafety level 3 laboratory was deployed on site for analysis of samples from both human and animal cases. The samples were analysed for B. anthracis according to the World Health Organization (WHO) guidelines and involved culture, isolation and confirmation of the isolates by polymerase chain reaction (WHO, 2008). The swabs and blood from suspected patients were directly inoculated on Blood agar (Himedia Laboratories Ltd., Mumbai, India) containing 5% sheep blood. The samples from animals and soil were decontaminated by subjecting them to heating in normal saline at 75ºC for 5 minutes. The fresh samples of tissues were inoculated directly on Blood agar.
The confirmed isolates of Bacillus anthracis were then subjected to antimicrobial susceptibility tests to define the profile of antimicrobial sensitivity, using standard antimicrobial discs on Mueller-Hinton agar (Difco; Becton, Dickinson and Co, Franklin Lakes, NJ, USA) followed by an E-test to determine the minimum inhibitory concentration (CLSI, 2008). The antibiotics tested with the disc diffusion method were penicillin, chloramphenicol, cotrimoxazole, erythromycin, doxycycline, tetracycline, streptomycin and gentamicin (Himedia Laboratories Ltd., Mumbai, India). Others were ciprofloxacin, amoxicillin, ampicillin and vancomycin (Oxoid Ltd., Basingstoke, UK). The MIC was determined for chloramphenicol,doxycycline, tetracycline, cotrimoxazole (Oxoid), ciprofloxacin, penicillin and erythromycin (Himedia Laboratories Ltd., Mumbai, India)

Figure 1. Skin lesion of anthrax on the feet

 

Figure 2. An ulcer and eschar with surrounding oedema

 Results

In this outbreak, 79 human cases and 25 carcasses (18 hippos and 7 buffalos) were identified. Of these human cases and animals, 12 human specimens and all animal samples were tested for Bacillus anthracis. Furthermore, lagoon water samples, soil samples from animal grave sites and land/pasture where animals graze from were also tested for Bacillus anthracis.

Table 1: Analysis of samples through culture, isolation and PCR

The tested hippo samples were negative while buffalo samples (2 buffalos) were positive for Bacillus anthracis. The water samples were negative while some soil samples from the hippo and buffalo grave site and pasture were positive (Table 1). Antimicrobial sensitivity patterns on the cultured 6 B. anthracis isolates indicated sensitivity to a range of drugs used. Intermediate sensitivity was observed with cotrimoxazole and erythromycin, while resistance with vancomycin was noted. The minimum inhibitory concentration of antimicrobial agents was observed at various points: chloramphenicol (8 µg/mL); doxycycline (0.5 µg/mL); tetracycline (1 µg/mL); ciprofloxacin (0.5 µg/mL); cotrimoxazole (16 µg/mL); penicillin (0.12 µg/mL); and erythromycin (4 µg/mL).Of the human cases of clinically confirmed anthrax identified the majority 41 (52%) were from Chikwa RHC followed by 24 (30%) from Pondo RHC. Of the total anthrax cases 48 (61%) were males. Overall, most cases (28%) were from the 5 – 14 age group (p<0.01). These results are shown in Table 2.

Table 2 Anthrax cases by age groups, health facility and exposure

Analysis of age group in each sex group revealed that amongst the males, most of the cases were aged between the 15-24 age-group (33%) followed by the 5 -14 (29%) whereas for females, it was highest among the less than 5 years and 5 – 14 age-group at 26% in both groups followed by those above 45 years (23%), as shown in Table 2. Analysis of differences between sexes in age groups showed a significant difference (p<0.001) between the sexes only in the 15 – 24 years age group. There was no significant difference (p=0.525) between children (<15 years) and adults (≥15years).

Clinical investigations noted the following signs and symptoms: eschar, rash like lesions among others. One patient had an allergic reaction features (figure 1 & 2). All cases except two were associated with consumption of dead hippo and/or buffalo meat. Of the two who had not eaten, one had eaten fish from the Baghdad lagoon where anthrax was confirmed and the other participated in butchering the carcasses.

The outbreak was contained within one month of onset between 19th September and 20th October 2016 (Figure 3). There were no fatalities

Figure 3 Epi-curve on anthrax outbreak in Chama, 2016

Discussion

An outbreak of cutaneous anthrax associated with Bacillus anthracis occurred in Chama district affecting almost a total of 80 children and adults with no significant difference between age groups and about 25animals. In this case another animal, the buffalo has come into the transmission pattern of anthrax. There were no positive results from hippopotamus. This could have been due to the decomposed carcasses. Bacillus anthracis is easily overrun by anaerobic bacteria upon death. This outbreak was less than that in the 2011 outbreak in the same district which affected about 520 humans with 6 deaths and 80 hippopotamus. Although there was no significant difference between age groups, it was noted on further analysis that in the 15 -25 age group there was a significant difference between males and females, with males more likely to be infected than females. This could be attributed to the fact that the males of this age group were the ones handling the carcasses to dismember them for meat.

All human cases identified were associated with eating either one or both of hippo and buffalo meat obtained from carcases in the outbreak area. Literature documents an association of anthrax infection with eating meat from infected carcasses or drinking contaminated water, through the skin by contact with infected material or by insect bites, and through the lungs by inhaling spores has been documented [19]. Some parts of Zambia are endemic of anthrax as evidenced by continued outbreaks impacting negatively on the economy of the livestock industry and public health generally. Social and economic determinants include poor food security resulting from draught in Chama area have been noted as contributing factors in these outbreaks. Despite knowing the consequences of eating infected meat, people prefer to get the disease than die from starvation. Similar determinants are described in the outbreaks in Western province [10]. This gap between knowledge and behavior became a threat to the communication effort that was mounted and required more interactive communication methods within the community to emphasise the dangers of anthrax and the importance of prevention and to promote community ownership and local solutions

The Anthrax outbreak in Chama was fueled by human behaviour, particularly that of handling dead animals. These risky behaviours have been well documented in similar outbreaks of anthrax where the need to educate communities was emphasized [20, 21, 22]. Although the people in Chama were aware about anthrax from previous outbreaks, it was very critical to sensitise the community and reinforce the knowledge on the causes, risk factors, signs and symptoms and to promote early care seeking. Early reporting of deaths of animals and wildlife by community members can also prevent the spread of anthrax. Equally, effective communication during an outbreak is important particularly using credical sources and ensuring the use of channels which can reach all the target audiences. The practice of communicating at different levels on a regular basis helped to build and to maintain trust of the community in line with WHO recommendations [24].

Another anthrax outbreak occurred in the same area in 2011. Chama district is located within a wildlife sanctuary, where normal anthrax intervention strategies cannot be applied. It has been documented that while livestock anthrax is generally on the decline in many parts of the world, it remains enzootic in many national parks, for example, in southern Africa and North America. This scenario represents a persistent risk for surrounding livestock and public health [19].

The timely containment and lack of any case fatalities may be attributed to the rapid response by the Ministry of Health with the support of the WHO country office in Zambia that provided financial resources (USD$7,176) and technical support (NPO/National Surveillance Officer and NPO/Health Promotion), National Parks and Wildlife (NPW) and the University of Zambia (UNZA) School of Veterinary Medicine Laboratory and Centre for Veterinary Research Institute (CVRI) who provided laboratory confirmation. A paper by Siamudaala et al. (2006) on the ecology and epidemiology of anthrax in some parts of Zambia indicated that challenges of anthrax control are complex and comprise of socio-political, economic, environmental and cultural factors. They also site inadequate funding, lack of innovative disease control strategies and lack of cooperation from stakeholders as the major constraints to the control of the disease in Zambia [10].

Having confirmed a clear picture of anthrax, the response included as part of the disease containment and prevention measures the following activities: confiscation and destruction of hippo meat and carcasses; active surveillance and contact training; treatment of cases and prophylaxis management of contacts; and community sensitisation including discouraging the community from eating dead animals. As a preventive measure for another outbreak in the same area, formalin and lime were applied to the soils where animas died from (animal graves) and where animals were being cut and shared by the people.

In order to ensure prevention and control for anthrax, enhanced surveillance which would include mechanisms for disease detection, confirmation of diagnosis, reporting, collation of data and feedback of the data to the source, must be employed [20].

Conflict of interest Statement

We declare that we have no conflict of interest.

Acknowledgements

The authors wish to thank the patients and care givers for being cooperative. The authors also acknowledge the efforts by the health staff (Health centre, district level, provincial level) and the Provincial Medical Officer put into the investigation and control of the outbreak

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