Cutaneous anthrax associated with handling carcasses of animals that died suddenly of unknown cause: Arua District, Uganda, January 2015–August 2017

• DOI: 10.21203/rs.2.22358/v1
• Publication Date: 2020-01-31T17:16:03Z
• Authors: Freda Loy Aceng; Alex Riolexus Ario; Phoebe Hilda Alit...; Daniel Kadobera; Musa Sekamatte; Denis Okethwangu; Lilian Bulage; Julie R. Harris; Willy Nguma; Deo Birungi Ndumu; Joshua Buule; Luke Nyakarahuka; Bao-Ping Zhu
• Keywords: 2. Zero hunger; 3. Good health

Abstract Background Anthrax is a vaccine-preventable disease that can be transmitted to humans from infected animals. During May–June 2017, three persons with suspected cutaneous anthrax were reported in Arua District, Uganda; one died. All had recently handled carcasses of livestock that died suddenly. During July, a bull in the same community died suddenly. A skin lesion from the deceased person and a blood sample from the bull tested positive by PCR for Bacillus anthracis. The aim of this investigation was to establish the scope of the problem, identify exposures associated with illness, and recommend evidence-based control measures.Methods We defined a probable case as acute onset of a papulo-vesicular skin lesion subsequently forming an eschar in a resident of Arua District during January 2015–August 2017. A confirmed case was a probable case with a skin sample testing positive by polymerase chain reaction (PCR) for B. anthracis . We identified cases by medical record review and active community search. In a case-control study, we compared exposures between case-patients and frequency- and village-matched asymptomatic controls. We interviewed key animal health staff to learn about livestock deaths.Results We identified 68 case-patients (67 probable, one confirmed), and two deaths. Cases occurred throughout the three-year period, peaking during dry seasons. All cases occurred following sudden livestock deaths in the villages. Case-patients came from two neighboring sub-counties: Rigbo (attack rate (AR)=20.1/10,000 population) and Rhino Camp (AR=2.1/10,000). Males (AR=17/100,000) were more affected than females (AR=0.52/100,000). Persons aged 30-39 years (AR=26/100,000 population) were most affected. Among all cases and 136 controls, skinning (OR M-H =5.0, 95%CI: 2.3–11), butchering (OR M-H =22, 95%CI: 5.5–89), and carrying the carcass of livestock that died suddenly (OR M-H =6.9, 95%CI: 3.0–16) were associated with illness.Conclusions Exposure to carcasses of animals that died suddenly was a risk factor for cutaneous anthrax in Arua District during 2015-2017. We recommended public education about signs and symptoms of anthrax, prompt treatment of illness following exposure to animals that died suddenly, and safe disposal of carcasses of animals that die suddenly. In addition, the anthrax burden in livestock should be investigated to inform the cost-effectiveness of livestock vaccination.