The exponential growth of the world population requires investing in food self-sufficiency, including the intake of meat proteins (Johnson, 1999). Arable land is needed, but across the Earth, only a third of the soil is suitable for agriculture (Kendall, 2000). However, in the Democratic Republic of the Congo (DRC), the eastern regions are endowed with arable soils and a favorable climate for livestock farming. Agriculture and pastoralism are the main income-generating activities in the eastern region, contributing to improved livelihood and the socio-economy of the area. Unfortunately, these regions have been under terror from armed groups whose presence and activities have profoundly affected agricultural activities for several decades. These armed groups indiscriminately raid and slaughter domestic animals from farmers but, as a countermeasure, constantly move their livestock. Farmers move into protected areas such as the Virunga national park and the surrounding interface areas. This scenario increases animal densities, over-utilization of common pool resources by livestock and wildlife, and increases opportunities for infectious disease transmission. Since farmers move with their livestock, there is an increased risk of emergence, re-emergence, and dissemination of infectious diseases, particularly zoonosis, such as anthrax.
Anthrax, also known as woolsorter’s disease, murrain, or spleen blood, is a multi-specie zoonotic disease caused by a spore-forming aero-anaerobic bacterium: Bacillus anthracis (B. anthracis). (Boseret et al., 2002; Sidwa et al., 2020). Except for Antarctica, anthrax is present and endemic on all continents and presents a socioeconomic and public health concern (Aikembayev et al., 2010; Sushma et al., 2021). However, the global distribution of B. anthracis is poorly understood; many countries, especially Africa, possess inadequate surveillance systems, even within known endemic regions (Carlson et al., 2018). This has resulted in under-reporting of the disease and, in some cases, neglected; thus, anthrax endemism and outbreak intensity has been characterized at extremely coarse scales. In animals and humans, the bacterium is often found in the vegetative form, but on exposure to air, it forms highly resistant spores that can remain viable for many years in some soils and therefore serves as a source of infection to grazing herbivores (Bakhteeva and Timofeev, 2022; Finke et al., 2020; Turner et al., 2014; Valseth et al., 2017). Thus, the ability of B. anthracis to form long-lasting, highly resistant spores is central to the persistence of anthrax in an area.
Once herbivores consume the spores, they germinate, changing to the growing and dividing vegetative form, which multiplies rapidly and causes the disease. B. anthracis virulence is due to the production of a tripartite toxin composed of a protective antigen, lethal factor, and edema factor (Brézillon et al., 2015; Mock and Fouet, 2001). The clinical manifestations vary depending on the location of the occurrence, the time of year, the susceptibility of the infected animal species, and the form of the disease (Kahn, 2008; Mongoh et al., 2008). It manifests as fatal febrile sepsis with or without hemorrhagic lymphadenitis (Fontaine and Cadoré, 1995; Kahn, 2008). Peracute septicemic forms are brutal, sometimes asymptomatic, and suddenly fatal (Boseret et al., 2002). On the lesional level, sticky, incoagulable, and blackish blood can flow from the body’s natural orifices (Kahn, 2008). Bulky and muddy spleen (spleen blood) and hemorrhages from the bladder are also observed (Boseret et al., 2002; Fontaine and Cadoré, 1995). Human anthrax cases are secondary to outbreaks in animals through contact or consumption of anthrax carcasses. There are three types of human anthrax infection: cutaneous, gastrointestinal, and pulmonary. The most common cutaneous form is acquired through contact, the gastrointestinal form through ingestion of infected meat, and the pulmonary form through inhalation of B. anthracis spores (Mock and Fouet, 2001; Musewa et al., 2022). “Hunger for meat,” being the primary driver of consumption of anthrax carcasses, contributed to environmental contamination with anthrax spores through the dressing of anthrax carcasses, a major source of primary infection for livestock and wildlife. These anthropogenic activities and the lack of knowledge of anthrax strongly intimate their contribution to anthrax recurrence and maintenance in endemic areas (Kamboyi et al., 2019).
Notwithstanding this context, anthrax can be controlled if animal species involved in its maintenance and transmission, anthropogenic factors, spatiotemporal distribution, and its impact on the human or animal population and the household economy are known. Unfortunately, due to poor animal health control and the absence of an effective surveillance system for animal diseases in the DRC, this zoonosis is not monitored, and the parameters contributing to its maintenance and dissemination are scarce or not documented. Furthermore, epizootic reports and alerts from park wardens and breeders are often under-reported and masked due to limited human resource, making this country's data on anthrax unavailable.
Therefore, this survey was designed to assess the knowledge regarding symptoms, transmission, and prevention of anthrax among farmers, to describe attitudes, and determine the risk and health-seeking practices in the event of anthrax. Simultaneously, the clinical investigation provides some evidence to understand, document, and report the epidemiology of this disease in the Kisongwere and Lulimbi groups and generate essential information for implementing appropriate measures for the control of anthrax in this environment.
Farmers in the North Kivu province frequently report morbidity and mortality suspecting Anthrax in domestic animals. Wild animal deaths are also sometimes reported with possible Anthrax signs. However, none of these alerts are investigated since the area is not secure because the decades-long war is still ongoing. Taking advantage of a given opportunity, a survey was conducted in 2015 that led to the gathering of information on the epidemiology of this disease in the area using verbal autopsy whereby farmers were interviewed on their knowledge, attitude, and practices related to Anthrax risk transmission and control. In 2021, alerts were reported by park guards on the mortality of buffaloes and hippopotamuses in the Virunga national park with suspected Anthrax signs. Despite the insecurity of the area, a team was sent to the field to conduct investigations on these cases. The present report underlines the findings of the 2015 survey and the 2021 investigations on Anthrax occurrence in this area.