Characteristics and Perspectives of Disease at the Wildlife-Livestock Interface in Africa

International audienc

Absence of Frequent Herpesvirus Transmission in a Nonhuman Primate Predator-Prey System in the Wild

Emergence of viruses into the human population by transmission from nonhuman primates (NHPs) represents a serious potential threat to human health that is primarily associated with the increased bushmeat trade. Transmission of RNA viruses across primate species appears to be relatively frequent. In contrast, DNA viruses appear to be largely host specific, suggesting low transmission potential. Herein, we use a primate predator-prey system to study the risk of herpesvirus transmission between different primate species in the wild. The system was comprised of western chimpanzees (Pan troglodytes verus) and their primary (western red colobus, Piliocolobus badius badius) and secondary (black-and-white colobus, Colobus polykomos) prey monkey species. NHP species were frequently observed to be coinfected with multiple beta- and gammaherpesviruses (including new cytomegalo- and rhadinoviruses). However, despite frequent exposure of chimpanzees to blood, organs, and bones of their herpesvirus-infected monkey prey, there was no evidence for cross-species herpesvirus transmission. These findings suggest that interspecies transmission of NHP beta- and gammaherpesviruses is, at most, a rare event in the wild

Vaccination against GnRH may suppress aggressive behaviour and musth in African elephant (Loxodonta africana) bulls - a pilot study

Aggressive behaviour and musth are constant problems in captive and sometimes in free-ranging African elephant bulls. Aggressive bulls are difficult and musth bulls almost impossible to manage without severely restricting their movement either by leg-chaining or using tranquillisers. This study investigated the relationship between faecal androgen metabolites (FAM) and faecal cortisol metabolites (FCM) concentrations and aggressive behaviour and tested aGnRHvaccine as a means of down-regulating aggressive behaviour and musth in 1 free-ranging and 5 captive elephant bulls. The bulls were non-aggressive (n = 3), aggressive (n = 2) or in musth (n = 1) at the onset of the study. The bulls were injected with a GnRH vaccine-adjuvant combination 3 or 4 times at 3- to 7-week intervals. Behaviour, FAM and FCM concentrations were measured during every week prior to vaccination until 4 months after the last vaccination. FAM concentrations were positively correlated with aggressive behaviour before the 1st vaccination. Androgen production, as reflected by FAM concentrations, was down-regulated in 3 of the 6 immunised bulls. At least 2 bulls and possibly a 3rd showed behavioural improvement followingGnRHvaccination and in all 3 temporal gland secretion ceased. No further aggressive behaviour was observed until the end of the study in any of the bulls. The results of this 1st GnRH immunisation study suggest that it could be a useful method to control aggressive behaviour and musth in African elephant bulls

Low Rates of Antimicrobial-Resistant Enterobacteriaceae in Wildlife in Taï National Park, Côte d’Ivoire, Surrounded by Villages with High Prevalence of Multiresistant ESBL-Producing Escherichia coli in People and Domestic Animals

Antimicrobial resistance genes can be found in all ecosystems, including those where antibiotic selective pressure has never been exerted. We investigated resistance genes in a collection of faecal samples of wildlife (non-human primates, mice), people and domestic animals (dogs, cats) in Côte d’Ivoire; in the chimpanzee research area of Taï National Park (TNP) and adjacent villages. Single bacteria isolates were collected from antibiotic-containing agar plates and subjected to molecular analysis to detect Enterobacteriaceae isolates with plasmid-mediated genes of extended-spectrum beta-lactamases (ESBLs) and plasmid-mediated quinolone resistance (PMQR). While the prevalence of ESBL-producing E. coli in the villages was 27% in people (n = 77) and 32% in dogs (n = 38), no ESBL-producer was found in wildlife of TNP (n = 75). PMQR genes, mainly represented by qnrS1, were also present in human- and dog-originating isolates from the villages (36% and 42% in people and dogs, respectively), but no qnrS has been found in the park. In TNP, different variants of qnrB were detected in Citrobacter freundii isolates originating non-human primates and mice. In conclusion, ESBL and PMQR genes frequently found in humans and domestic animals in the villages were rather exceptional in wildlife living in the protected area. Although people enter the park, the strict biosecurity levels they are obliged to follow probably impede transmission of bacteria between them and wildlife

Dynamics of Antibodies to Ebolaviruses in an Eidolon helvum Bat Colony in Cameroon

International audienceThe ecology of ebolaviruses is still poorly understood and the role of bats in outbreaks needs to be further clarified. Straw-colored fruit bats (Eidolon helvum) are the most common fruit bats in Africa and antibodies to ebolaviruses have been documented in this species. Between December 2018 and November 2019, samples were collected at approximately monthly intervals in roosting and feeding sites from 820 bats from an Eidolon helvum colony. Dried blood spots (DBS) were tested for antibodies to Zaire, Sudan, and Bundibugyo ebolaviruses. The proportion of samples reactive with GP antigens increased significantly with age from 0–9/220 (0–4.1%) in juveniles to 26–158/225 (11.6–70.2%) in immature adults and 10–225/372 (2.7–60.5%) in adult bats. Antibody responses were lower in lactating females. Viral RNA was not detected in 456 swab samples collected from 152 juvenile and 214 immature adult bats. Overall, our study shows that antibody levels increase in young bats suggesting that seroconversion to Ebola or related viruses occurs in older juvenile and immature adult bats. Multiple year monitoring would be needed to confirm this trend. Knowledge of the periods of the year with the highest risk of Ebolavirus circulation can guide the implementation of strategies to mitigate spill-over events

Characteristics of ESBL-producing isolates from villages.

<p>All isolates were obtained on MCA-cefotaxime.</p><p>“D” – isolate from dog, “H” – isolates from human, “C” – isolate from cat. “T” in brackets means that the resistance gene was successfully transformed into competent cells, “C” in brackets means that the gene was conjugated. Plasmids were isolated and characterized from isolates in bold font. See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0113548#pone-0113548-t002" target="_blank">Table 2</a> for plasmid characteristics.</p><p>PG = phylogroup, Amp = ampicillin, Cef = cephalotin, Caz = ceftazidime, Amc = amoxycilin-clavulanate, Nal = nalidixic acid, Cip = ciprofloxacin, Tet = tetracycline, Sxt = trimethoprim-sulfamethoxazole, Spt = streptomycin, Sul = sulfonamides compounds, Gen = gentamicin, Chl = chloramphenicol, Cpd = cefpodoxime.</p><p>Characteristics of ESBL-producing isolates from villages.</p

Dendrogram of resistant <i>E. coli</i> isolates’ PFGE profiles.

<p>Generated by cluster analysis of the Dice similarity indices in the BioNumerics fingerprinting software (optimization 1%, band matching tolerance 1%, tolerance change 1%). Isolates marked with “cip” were obtained by cultivation on ciprofloxacin and harbored PMQR genes, isolates with “ctx” represent the CTX-M-15 producing <i>E. coli</i>. “H” isolate from human, “D” isolate from dog, “C” isolate from cat.</p

Characteristics of isolates with PMQR genes.

<p>Isolates were obtained on MCA-ciprofloxacin.</p><p>For legend see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0113548#pone-0113548-t001" target="_blank">table 1</a>.</p><p>Characteristics of isolates with PMQR genes.</p

Characteristics of plasmids obtained by transformation.

<p>“NT”–not typable. Note: transconjugants obtained in this study contained more than one plasmid and therefore were not used for plasmid characterization.</p><p>Characteristics of plasmids obtained by transformation.</p