Cutaneous anthrax outbreak associated with handling dead animals, Rhino Camp sub-county: Arua District, Uganda, January-May 2018

Anthrax outbreak linked to consumption and handling of meat from unexpectedly deceased cattle, Kyotera district, Uganda, June-December 2023

BACKGROUND

Anthrax is an infectious zoonotic disease caused by gram-positive, rod-shaped, and spore-forming bacteria known as Bacillus anthracis. It continues to be a disease of public health importance in Uganda, with sporadic outbreaks reported annually in many parts of the country. In November 2023, Kyotera District reported a strange illness, characterized by itching, rash, swelling, and skin lesions which was later confirmed as anthrax. We investigated to assess its magnitude, identify potential exposures, and propose evidence-based control measures.

METHODS

A suspected cutaneous anthrax case was an acute onset of skin itching/swelling plus ≥ 2 of: skin reddening, lymphadenopathy, headache, fever or general body weakness. A suspected gastrointestinal anthrax case was an acute onset of ≥ 2 of: abdominal pain, vomiting, diarrhea, mouth lesions or neck swelling. A confirmed anthrax case was a suspected case with Bacillus anthracis PCR-positive results. To identify cases, we reviewed medical records and conducted community active case-finding. We conducted an unmatched case-control study and used logistic regression to identify risk factors of anthrax transmission. Controls were selected at a 1:4 ratio from the same villages as the case-patients.

RESULTS

We identified 63 cases (46 suspected and 17 confirmed); 48 (76%) were male. Of the 63, 55 cases (87%) were cutaneous and 8 (13%) were gastrointestinal, with a mean age of 42 years. Overall attack rate (AR) was 3.1/1,000; males were more affected (AR = 4.5/1,000) than females (AR = 1.5/1,000). Case-fatality rate was 19% (n = 12). Among the 63 cases, 18 (29%) sought care from health facilities; 33 (52%) were managed by traditional healers. The odds of anthrax infection were highest in individuals who both consumed and handled infected meat (OR = 20.9, 95% CI: 8.8-49.8), followed by those who only consumed the meat (OR = 5.81, 95% CI: 2.12-15.9).

CONCLUSION

The anthrax outbreak in Kyotera District was primarily attributed to the consumption and handling of meat from cattle that had suddenly died. Poor health-seeking behavior and seeking care from traditional healers likely contributed to the high case fatality rate. To prevent future outbreaks, authorities should enforce cattle inspection protocols, expand anthrax vaccination campaigns, and enhance community education on safe meat handling and medical care-seeking practices.

Time to control of anthrax outbreaks in Africa, 2014-2023: A systematic review and meta-analysis

Anthrax is a notifiable zoonotic disease targeted for control in Africa, however, outbreaks due to anthrax are still frequent and large. Surveillance systems should monitor and detect anthrax outbreaks early for prompt response. This systematic review and meta-analysis aimed to determine anthrax outbreaks epidemiological investigations gaps and time to control in Africa, Jan 2014-Dec 2023. We searched MEDLINE, PubMed, Scopus, Embase, Google Scholar, and Web of Science databases using PICO framework for studies on anthrax investigations. Using Covidence, we screened and extracted studies, analysed descriptive data using Microsoft Excel and quantitative data using RStudio version 4.3.1. We calculated heterogeneity and confidence intervals around pooled effect and performed risk of bias assessment. Ten of 1,639 studies met eligibility criteria and were included. Pooled median duration to control was 40.5 (IQR 80.8) days and estimated duration of outbreak end was 59.2 days (95% CI: 7.4-111.0), far beyond two incubation periods of anthrax (14 days). Median time to alert was 5 days (95% CI:0-490). A third (30%) didn't investigate animal anthrax. No study reported use of all levels of case definitions, and no study translated case investigation forms into local languages. A third (30%) of studies omitted time component of descriptive epidemiology and 22% of studies used cross-sectional study design. All studies used epidemiologists for case investigations, with 90% employing field epidemiologists, only one study used a social worker. Only 20% of studies used government funds; majority (80%) instituted public health actions. Risk of bias was at 0-20%. Median duration to control was greater than two anthrax incubation periods indicating delayed response. Several epidemiological gaps including delayed outbreak verification, focus on human anthrax and neglect of zoonotic aspects, and inappropriate working case definitions were highlighted. Timely and comprehensive epidemiological investigations, with a One Health approach to anthrax outbreak control is recommended. Systematic Review Registration: The protocol that guided this review was registered on PROSPERO: CRD42024498034.

Identification of Anthrax as the Cause of a Cluster of Unexplained Deaths, Uganda, 2023: The Role of Metagenomic Next-Generation Sequencing and Postmortem Specimens

Between April and November 2023, 27 unexplained human deaths that presented with swelling of the arms, skin sores with black centers, difficulty in breathing, obstructed swallowing, headaches, and other body aches were reported in Kyotera District, Uganda by the Public Health Emergency Operations Center. Subsequently, the death of cattle on farms and the consumption of carcass meat by some residents were also reported. Field response teams collected clinical/epidemiological data and autopsy samples to determine the cause of deaths. Metagenomic next-generation sequencing (mNGS) and target enrichment sequencing conducted on postmortem samples confirmed Bacillus anthracis, the etiological agent of anthrax disease, as the cause of the deaths. Applying mNGS to autopsy specimens is useful as a retrospective tool for identifying high-consequence pathogens during suspected outbreaks of unknown etiology.

Anthrax Outbreaks in Kyotera District, Uganda: Implications for Public Health Emergency Preparedness

Introduction

In late 2023, Uganda's Ministry of Health declared an anthrax outbreak in the Kyotera district, Masaka region, following reported animal and human fatalities. This article outlines the initial outbreak characteristics and the multi-sectoral response initiated by national and international stakeholders.

Methodology

This article presents a descriptive account of the anthrax outbreak in Kyotera district based on preliminary investigations, surveillance data provided by the Ministry of Health and collaborating partners (WHO, Infectious Disease Institute, Public Health Fellowship Program, Masaka Regional PHEOC), and a review of the unfolding events up to October 31, 2023.

Results

The anthrax outbreak in Kyotera district significantly impacted both human and livestock populations, leading to confirmed human cases, fatalities, and the death of 24 animals by October 31, 2023. The outbreak disrupted community livelihoods and strained the healthcare system, particularly as Uganda continues its recovery from the COVID-19 pandemic. Preliminary observations suggest a potential link between the outbreak and the rainy season, consistent with previous anthrax occurrences in East Africa. Economic consequences included potential job losses in the local meat industry and increased demands on healthcare resources.

Conclusion

The recent anthrax outbreak in Kyotera district underscores the ongoing threat of zoonotic diseases and the importance of a swift, coordinated, and multi-sectoral response. The findings highlight the need for strengthened interministerial cooperation, proactive health education campaigns targeting at-risk communities, consideration of prophylactic interventions, and the adoption of a comprehensive One Health approach for effective prevention and control of future outbreaks in Uganda.

Spatial analysis of human and livestock anthrax in Lai Chau province, Vietnam (2004-2021)

Anthrax is reported globally with varying disease intensity and seasonality among countries. In Vietnam, anthrax epidemiology and ecology remain understudied. We used historical data of human and livestock anthrax from 2004 to 2021 in Lai Chau province, to identify spatial clusters of human and livestock anthrax, describe epidemiological characteristics, and compare livestock anthrax vaccine coverage to human and livestock disease incidence. Local Moran's I (LISA) using spatial Bayes smoothed commune-level cumulative incidence (per 10,000) for the study period, epidemiological descriptive statistics, livestock vaccine coverage data, and annual incidence rates (per 10,000) at provincial level were used. LISA identified a human anthrax hotspot (high-high) in the southeast which did not overlap spatially with livestock anthrax hotspots in southeastern and northeastern communes. Most human cases were male, aged 15-59 years, handled sick animals, and/or consumed contaminated meat. Almost all cases were reported by grassroot health facilities with a delay of 6.3 days between exposure and case notification to the national surveillance system. 80 % of human cases were reported from June-October. The increase in disease incidence occurred shortly after livestock anthrax vaccine coverage decreased. This study informs vaccination strategy and targeted surveillance and control measures in newly identified high-risk areas and seasons of anthrax.

Informing One Health Anthrax Surveillance and Vaccination Strategy from Spatial Analysis of Anthrax in Humans and Livestock in Ha Giang Province, Vietnam (1999-2020)

Anthrax, caused by Bacillus anthracis, has a nearly global distribution but is understudied in Southeast Asia, including Vietnam. Here, we used historical data from 1999 to 2020 in Ha Giang, a province in northern Vietnam. The objectives were to describe the spatiotemporal patterns and epidemiology of human and livestock anthrax in the province and compare livestock vaccine coverage with human and livestock anthrax incidence. Annual incidence rates (per 10,000) for humans, buffalo/cattle, and goats were used to explore anthrax patterns and for comparison with livestock annual vaccine variations. A data subset describes anthrax epidemiology in humans by gender, age, source of infection, type of anthrax, admission site, and season. Zonal statistics and SaTScan were used to identify spatial and space-time clusters of human anthrax. SaTScan revealed space-time clusters in 1999, 2004, and 2007-2008 in the province, including in the northeastern, eastern, and western areas. Most human anthrax was reported between July and October. Most patients were male, aged 15-59 years, who had handled sick animals and/or consumed contaminated meat. High case-fatality rates were reported with gastrointestinal or respiratory cases. Our data suggest that vaccination in buffalo and cattle reduces the disease burden in humans and vaccinated animals but does not reduce the incidence in unvaccinated animals (goats). This study identified spatial areas of high risk for anthrax and can inform One Health surveillance and livestock vaccination planning in contextual settings similar to Ha Giang province.

Improving the effectiveness of Field Epidemiology Training Programs: characteristics that facilitated effective response to the COVID-19 pandemic in Uganda

BACKGROUND

The global need for well-trained field epidemiologists has been underscored in the last decade in multiple pandemics, the most recent being COVID-19. Field Epidemiology Training Programs (FETPs) are in-service training programs that improve country capacities to respond to public health emergencies across different levels of the health system. Best practices for FETP implementation have been described previously. The Uganda Public Health Fellowship Program (PHFP), or Advanced-FETP in Uganda, is a two-year fellowship in field epidemiology funded by the U.S. Centers for Disease Control and situated in the Uganda National Institute of Public Health (UNIPH). We describe how specific attributes of the Uganda PHFP that are aligned with best practices enabled substantial contributions to the COVID-19 response in Uganda.

METHODS

We describe the PHFP in Uganda and review examples of how specific program characteristics facilitate integration with Ministry of Health needs and foster a strong response, using COVID-19 pandemic response activities as examples. We describe PHFP activities and outputs before and during the COVID-19 response and offer expert opinions about the impact of the program set-up on these outputs.

RESULTS

Unlike nearly all other Advanced FETPs in Africa, PHFP is delinked from an academic degree-granting program and enrolls only post-Master's-degree fellows. This enables full-time, uninterrupted commitment of academically-trained fellows to public health response. Uganda's PHFP has strong partner support in country, sufficient technical support from program staff, Ministry of Health (MoH), CDC, and partners, and full-time dedicated directorship from a well-respected MoH staff member. The PHFP is physically co-located inside the UNIPH with the emergency operations center (EOC), which provides a direct path for health alerts to be investigated by fellows. It has recognized value within the MoH, which integrates graduates into key MoH and partner positions. During February 2020-September 2021, PHFP fellows and graduates completed 67 major COVID-related projects. PHFP activities during the COVID-19 response were specifically requested by the MoH or by partners, or generated de novo by the program, and were supervised by all partners.

CONCLUSION

Specific attributes of the PHFP enable effective service to the Ministry of Health in Uganda. Among the most important is the enrollment of post-graduate fellows, which leads to a high level of utilization of the program fellows by the Ministry of Health to fulfill real-time needs. Strong leadership and sufficient technical support permitted meaningful program outputs during COVID-19 pandemic response. Ensuring the inclusion of similar characteristics when implementing FETPs elsewhere may allow them to achieve a high level of impact.

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

Background

Anthrax is a zoonotic infection caused by the bacteria Bacillus anthracis. Humans acquire cutaneous infection through contact with infected animals or animal products. On May 6, 2018, three cows suddenly died on a farm in Kiruhura District. Shortly afterwards, a sub-county chief in Kiruhura District received reports of humans with suspected cutaneous anthrax in the same district. The patients had reportedly participated in the butchery and consumption of meat from the dead cows. We investigated to determine the magnitude of the outbreak, identify exposures associated with illness, and suggest evidence-based control measures.

Methods

We conducted a retrospective cohort study among persons whose households received any of the cow meat. We defined a suspected human cutaneous anthrax case as new skin lesions (e.g., papule, vesicle, or eschar) in a resident of Kiruhura District from 1 to 26 May 2018. A confirmed case was a suspected case with a lesion testing positive for B. anthracis by polymerase chain reaction (PCR). We identified cases through medical record review at Engari Health Centre and active case finding in the community.

Results

Of the 95 persons in the cohort, 22 were case-patients (2 confirmed and 20 suspected, 0 fatal cases) and 73 were non-case household members. The epidemic curve indicated multiple point-source exposures starting on May 6, when the dead cows were butchered. Among households receiving cow meat, participating in slaughtering (RR = 5.3, 95% CI 3.2–8.3), skinning (RR = 4.7, 95% CI = 3.1–7.0), cleaning waste (RR = 4.5, 95% CI = 3.1–6.6), and carrying meat (RR = 3.9, 95% CI = 2.2–7.1) increased the risk of infection.

Conclusions

This cutaneous anthrax outbreak was caused by handling infected animal carcasses. We suggested to the Ministry of Agriculture, Animal Industry and Fisheries to strengthen surveillance for possible veterinary anthrax and ensure that communities do not consume carcasses of livestock that died suddenly. We also suggested that the Ministry of Health equip health facilities with first-line antibiotics for community members during outbreaks.