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Recovering from an Anthrax epidemic: What are the control strategy challenges and policy options?

A Moraes

Ministry of Health, Ndeke House, Lusaka, Zambia

Correspondence: Albertina Moraes (albertina.ngomah@gmail.com)

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Moraes A. Recovering from an Anthrax epidemic: What are the control strategy challenges and policy options? Health Press Zambia Bull. 2017;1(1) pp63-66

Anthrax is endemic in parts of Zambia, triggered annually by an interplay of environmental factors and human activity. Anthrax cases are typically reported between June and December, coinciding with the period when the human population density on the floodplain is high. Case fatality rate usually ranges from 4-20%. Anthrax impacts negatively on both public health and the livestock industry.
Zambia’s Western province is currently in the middle of an anthrax epidemic; both humans and animals are affected. There have been 77 human cases (with 5 deaths reported) since the outbreak began in November 2016. The number of animal cases is unconfirmed as some livestock owners withhold information of animal deaths from officials.
Zambia presently relies on the Technical Guidelines for Integrated Disease Surveillance and Response as well as the WHO Anthrax Guidelines to guide its actions during anthrax outbreaks.
Quarantines, mass vaccinations and restricted movement of livestock, as well as public awareness campaigns have been initiated to contain the outbreak


Key Surveillance Findings as of 31 January 2017

As of 29 January 2017, no new cases had been reported. A total of 72 cumulative cases have been recorded since the outbreak began: 25 from Shangombo, 9 from Nalolo, 37 from Kalabo and 1 from Limulunga. Of the 5 deaths reported, 3 were reported from the facility in Kalabo while 2 were reported from the communities in Shangombo and Kalabo. There are six cases currently under treatment as out-patients. The case fatality rate presently stands at 4%.

The Provincial Health Office has been transporting specimens to Lusaka for official analysis and results. Collaboration with the veterinary department is yielding results as the department has begun distributing vaccines to vaccinate animals in affected areas. Information, Education and Communication (IEC) campaigns have continued. However, one of the major challenges being faced is community members who have continued to eat the meat from infected carcasses, disregarding sensitisation messages against this practice.

The above is a depiction of the outbreak in Shangombo, one of the affected Districts. The index case, whose illness was associated with consuming meat from bovine carcasses, was reported on 11/11/2016 from Tukombwe village. There was a spike in the number of cases after 3 animals died in Sikowe village. Remains were destroyed by a combined team of Provincial Health Office, District Health Office and health facility staff. Sensitisation of the community was done. All cases were put on treatment. District and health centre staff are conducting active case investigation and community sensitisation

Research gaps and control challenges

Further research into the molecular epidemiology of the disease as well as strain identification and differentiation will enhance epidemiological investigations and understanding of anthrax not only at national level, but at regional level as well.

Currently used control strategies involving mass vaccinations, quarantine, burning or burying of animal carcasses and community sensitisation fall short in the control of anthrax. Farmers tend to be uncooperative with vaccination of livestock as it coincides with the farming season and thus is viewed as a disruption to the maximum usage of animals for farming activities. Quarantine tends to be difficult to enforce due to numerous illegal routes used to transport livestock.

Communities are often reluctant to burn or bury carcasses as advised. In the flood plains where epidemics commonly occur, there is a lack of firewood to burn the carcasses. The burning of carcasses is also seen as time consuming and a distraction from farming activities. Carcasses are salvaged for meat, despite health warnings, which results in human cases. Furthermore, inhalation of spores through exposure to hides from infected carcasses that were processed for use as sleeping mats or drums has been noted to play a minor role in proliferation of epidemics.

Policy options

A one-health approach is key to achieving lasting control of anthrax. Surveillance systems must be strengthened for early detection and response.
Human Vaccination campaigns: The most effective method for mass protection against anthrax is through vaccination. Mandatory vaccinations in endemic areas (with the exception of individuals with a history of anthrax disease and pregnant women until after delivery) would reduce disease incidence by up to 92.5%, based on human and animal data.

Animal vaccination campaigns must be conducted at regular intervals. The timing of these campaigns must not coincide with the farming season so as to increase uptake by farmers. Increasing the vaccination coverage through continued collaboration between the public and private sector, and instituting a systematic quality control programme to evaluate the performance of vaccination campaigns will increase the likelihood of success of such programmes.

Investing in infrastructure for local vaccine production: the Central Veterinary Laboratory under the Department of Veterinary and Livestock Development, currently produces a local vaccine with high potency and no side effects. This should be scaled up throughout the provinces so as to decentralise the technical and administrative support required for control of epidemics. Stockpiles of the vaccine should be available for use during epidemics; these can then be transported promptly to outbreak areas by means such as drones.

Scaling up community outreach activities in endemic areas to ensure timely treatment of cases and a reduction in anthrax mortalities, especially for communities in hard to reach areas where the long distances to facilities often affects access to care. Furthermore, salient health information and mass media campaigns must be designed and implemented regularly to further educate the public regarding the dangers of consuming meat from infected carcasses as well as using hides from animals dying of anthrax

Improving food security in outbreak prone areas will further reduce instance of carcass salvage by local communities.

Available literature

  1. Ministry of Health Situation Reports, Surveillance Data, 2016-2017.
  2. Hang’ombe, M.B., Mwansa, J.C., Muwowo, S., Mulenga, P., Kapina, M., Musenga, E., Squarre, D., Mataa, L., Thomas, S.Y., Ogawa, H. and Sawa, H., 2012. Human–animal anthrax outbreak in the Luangwa valley of Zambia in 2011. Tropical doctor, 42(3), pp.136-139.
  3. Munang’andu, H.M., Banda, F., Siamudaala, V.M., Munyeme, M., Kasanga, C.J. and Hamududu, B., 2012. The effect of seasonal variation on anthrax epidemiology in the upper Zambezi floodplain of western Zambia. Journal of veterinary science, 13(3), pp.293-298.
  4. Ohnishi, N., Maruyama, F., Ogawa, H., Kachi, H., Yamada, S., Fujikura, D., Nakagawa, I., Hang’ombe, M.B., Thomas, Y., Mweene, A.S. and Higashi, H., 2014. Genome sequence of a Bacillus anthracis outbreak strain from Zambia, 2011. Genome announcements2(2), pp.e00116-14.
  5. Siamudaala, V.M., Bwalya, J.M., Munang’andu, H.M., Sinyangwe, P.G., Banda, F., Mweene, A.S., Takada, A. and Kida, H., 2006. Ecology and epidemiology of anthrax in cattle and humans in Zambia. Japanese Journal of Veterinary Research, 54(1), pp.15-23.
  6. Turnbull, P.C., Bell, R.H., Saigawa, K., Munyenyembe, F.E., Mulenga, C.K. and Makala, L.H., 1991. Anthrax in wildlife in the Luangwa Valley, Zambia. The Veterinary Record, 128(17), pp.399-403.
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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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