Cutaneous Anthrax Outbreak Associated with Handling Dead Animals, Rhino Camp Sub-county: Arua District, Uganda, January-May2018

Abstract

Background: On the 9 February 2018, Arua District notified Uganda Ministry of Health of a confirmed anthrax outbreak among humans in Rhino Camp sub-county. Many persons fell ill after reported contact with livestock that died suddenly. We investigated to determine the scope, mode of transmission and exposures associated with identified anthrax, to guide control and prevention measures. Methods: We defined a suspected cutaneous anthrax case as onset of skin lesions (e.g., papule, vesicle, or eschar) in a person residing in Rhino Camp sub-county, Arua District from 25 December, 2017 to 31 May, 2018. A confirmed case was a suspected case with PCR-positivity for Bacillus anthracis from a clinical sample. We identified cases by reviewing medical records at Rhino Camp Health Centre. We also conducted additional case searches in the affected community with support from Community Health Workers. In a retrospective cohort study, we interviewed all members of households in which at least one person had contact with the carcasses of or meat from animals suspected to have died of anthrax. We collected and tested hides of implicated animals using an anthrax rapid diagnostic test.Results: We identified 14 case-patients (1 confirmed, 13 suspected); none died. Only males were affected (AR: 12/10,000). Mean age of case-persons was 33years (SD: 22).The epidemic curve shows that the outbreak lasted for 5 months, from January 2018-May 2018, peaking in February.Skinning(RR=2.7, 95%CI=1.1-6.7), dissecting (RR=3.0, 95%CI=1.2-7.6), and carrying the dead animals (RR=2.7, 95%CI=1.1-6.7) were associated with increased risk of illness, as were carrying dissected parts of the animal (RR=2.9, 95%CI 1.3-6.5) and preparing and cooking the meat (RR=2.3, 95%CI 2.7-8.1). We found evidence of animal remains on pastureland.Conclusion: Multiple exposures to the hides and meat of animals that died suddenly were associated with this cutaneous anthrax outbreak in Arua District. We recommended public education about safe disposal of carcasses of livestock that die suddenly.

Outbreak of cutaneous anthrax associated with handling meat of dead cows in Southwestern Uganda, May 2018

“…These factors were present most likely influencing the anthrax outbreak in both animals and humans. Previous investigations of outbreaks in Uganda that have been done recently also found the association of anthrax to handling of meat from animals that died suddenly [4,6,17].…”

“…Contact with livestock included skinning, slaughtering, carrying meat and cleaning the carcasses of the animals. These are mainly male-dominated roles which explains why males are usually the most affected subpopulation during anthrax outbreaks [4,6,18].…”

“…These outbreaks have mainly been reported in areas. where people commonly keep livestock majorly within western, eastern and northern Uganda [4][5][6]. Vaccination rates of livestock in sub-Saharan Africa are very low, 0-6%, hence the risk of infection with anthrax in livestock is high [2].…”