Low antibody prevalence against Bacillus cereus biovar anthracis in Taï National Park, Côte d'Ivoire, indicates high rate of lethal infections in wildlife

Bacillus cereus biovar anthracis (Bcbva) is a member of the B. cereus group which carries both B. anthracis virulence plasmids, causes anthrax-like disease in various wildlife species and was described in several sub-Saharan African rainforests. Long-term monitoring of carcasses in Taï National Park, Côte d’Ivoire, revealed continuous wildlife mortality due to Bcbva in a broad range of mammalian species. While non-lethal anthrax infections in wildlife have been described for B. anthracis, nothing is known about the odds of survival following an anthrax infection caused by Bcbva. To address this gap, we present the results of a serological study of anthrax in five wildlife species known to succumb to Bcbva in this ecosystem. Specific antibodies were only detected in two out of 15 wild red colobus monkeys (Procolobus badius) and one out of 10 black-and-white colobus monkeys (Colobus polykomos), but in none of 16 sooty mangabeys (Cercocebus atys), 9 chimpanzees (Pan troglodytes verus) and 9 Maxwell’s duikers (Cephalophus maxwellii). The combination of high mortality and low antibody detection rates indicates high virulence of this disease across these different mammalian species

Serological evidence for human exposure to Bacillus cereus biovar anthracis in the villages around Taï National Park, Côte d'Ivoire.

Bacillus cereus biovar anthracis (Bcbva) is an untypical anthrax-causing pathogen responsible for high wildlife mortality in Taï National Park (TNP), Côte d'Ivoire. However, nothing is known about its effect on the rural population living in the region bordering TNP. Contact to bushmeat is a known risk factor for exposure to a variety of zoonotic pathogens, but no human infections with Bcbva were noted so far. Therefore, we performed a retrospective seroprevalence analysis with sera from 1,386 study volunteers. We used assays which detect antibodies against the protective antigen PA, which is synthesized by both Bcbva and classic B. anthracis, and against the recently described antigen pXO2-60, a 35-kDa protein only produced by Bcbva. We found a high seroprevalence (22.37%) of antibodies against PA, and approximately half of those sera (10.46%) were also positive for the Bcbva-specific antigen pXO2-60. All sera negative for PA were also negative for antibodies against pXO2-60, confirming specificity and suitability of the PA/pXO2-60 combined serological assay. The fact that a large fraction of sera was positive for PA but negative for pXO2-60 can most likely be explained by lower immunogenicity of pXO2-60, but exposure to classic B. anthracis cannot be excluded. As only Bcbva has been detected in the TNP area so far, exposure to Bcbva can be suspected from the presence of antibodies against PA alone. In a questionnaire, most study participants reported contact to bushmeat and livestock carcasses. Unfortunately, risk factor analysis indicated that neither animal contacts, sex, age, nor country of origin were significant predictors of Bcbva seroprevalence. Nevertheless, our study added to an assessment of the distribution of Bcbva and its impact on the human population, and our data can serve to raise awareness of anthrax in the affected regions

Outbreak of Tularemia in a Group of Hunters in Germany in 2018—Kinetics of Antibody and Cytokine Responses

In November 2018, an outbreak of tularemia occurred among hare hunters in Bavaria, Germany. At least one infected hare was confirmed as the source of infection. A number of hunting dogs showed elevated antibody titers to Francisella tularensis, but the absence of titer increases in subsequent samples did not point to acute infections in dogs. Altogether, 12 persons associated with this hare hunt could be diagnosed with acute tularemia by detection of specific antibodies. In nine patients, the antibody and cytokine responses could be monitored over time. Eight out of these nine patients had developed detectable antibodies three weeks after exposure; in one individual the antibody response was delayed. All patients showed an increase in various cytokines and chemokines with a peak for most mediators in the first week after exposure. Cytokine levels showed individual variations, with high and low responders. The kinetics of seroconversion has implications on serological diagnoses of tularemia

<i>Bcbva</i> positive necropsies in Taï National Park from 2006 to 2015.

<p>Taï National Park is located in the south-west of Côte d’Ivoire near the Liberian border (0°15’– 6°07’N, 7°25’– 7°54’W). The box in the overview map indicates the area enlarged in the big map. Carcass monitoring has revealed continuous occurrence of <i>Bcbva</i> in the research area (marked in gray in the big map) of the Taï Chimpanzee Project. All tested serological samples were collected in this area between 2006 and 2015. The 62 out of 139 (45%) carcasses that tested positive for <i>Bcbva</i> in this period are indicated in the map. Blue dots show duiker carcasses, red dots monkey carcasses and black dots chimpanzee carcasses. The figure has been created by the authors of the manuscript with the freely available software QGIS. Shape files for Africa were freely available at <a href="http://maplibrary.org/library/index.htm" target="_blank">http://maplibrary.org/library/index.htm</a>.</p

Low antibody prevalence against <i>Bacillus cereus</i> biovar <i>anthracis</i> in Taï National Park, Côte d'Ivoire, indicates high rate of lethal infections in wildlife

<div><p><i>Bacillus cereus</i> biovar <i>anthracis (Bcbva)</i> is a member of the <i>B</i>. <i>cereus</i> group which carries both <i>B</i>. <i>anthracis</i> virulence plasmids, causes anthrax-like disease in various wildlife species and was described in several sub-Saharan African rainforests. Long-term monitoring of carcasses in Taï National Park, Côte d’Ivoire, revealed continuous wildlife mortality due to <i>Bcbva</i> in a broad range of mammalian species. While non-lethal anthrax infections in wildlife have been described for <i>B</i>. <i>anthracis</i>, nothing is known about the odds of survival following an anthrax infection caused by <i>Bcbva</i>. To address this gap, we present the results of a serological study of anthrax in five wildlife species known to succumb to <i>Bcbva</i> in this ecosystem. Specific antibodies were only detected in two out of 15 wild red colobus monkeys (<i>Procolobus badius</i>) and one out of 10 black-and-white colobus monkeys (<i>Colobus polykomos</i>), but in none of 16 sooty mangabeys (<i>Cercocebus atys</i>), 9 chimpanzees (<i>Pan troglodytes verus</i>) and 9 Maxwell’s duikers (<i>Cephalophus maxwellii</i>). The combination of high mortality and low antibody detection rates indicates high virulence of this disease across these different mammalian species.</p></div

Results overview.

<p>Results overview.</p