Geographical distribution and relative risk of Anjozorobe virus (Thailand orthohantavirus) infection in black rats (Rattus rattus) in Madagascar

Abstract

BackgroundHantavirus infection is a zoonotic disease that is associated with hemorrhagic fever with renal syndrome and cardiopulmonary syndrome in human. Anjozorobe virus, a representative virus of Thailand orthohantavirus (THAIV), was recently discovered from rodents in Anjozorobe-Angavo forest in Madagascar. To assess the circulation of hantavirus at the national level, we carried out a survey of small terrestrial mammals from representative regions of the island and identified environmental factors associated with hantavirus infection. As we were ultimately interested in the potential for human exposure, we focused our research in the peridomestic area.MethodsSampling was achieved in twenty districts of Madagascar, with a rural and urban zone in each district. Animals were trapped from a range of habitats and examined for hantavirus RNA by nested RT-PCR. We also investigated the relationship between hantavirus infection probability in rats and possible risk factors by using Generalized Linear Mixed Models.ResultsOverall, 1242 specimens from seven species were collected (Rattus rattus, Rattus norvegicus, Mus musculus, Suncus murinus, Setifer setosus, Tenrec ecaudatus, Hemicentetes semispinosus). Overall, 12.4% (111/897) of Rattus rattus and 1.6% (2/125) of Mus musculus were tested positive for THAIV. Rats captured within houses were less likely to be infected than rats captured in other habitats, whilst rats from sites characterized by high precipitation and relatively low seasonality were more likely to be infected than those from other areas. Older animals were more likely to be infected, with infection probability showing a strong increase with weight.ConclusionsWe report widespread distribution of THAIV in the peridomestic rats of Madagascar, with highest prevalence for those living in humid areas. Although the potential risk of infection to human may also be widespread, our results provide a first indication of specific zone with high transmission. Gathered data will be helpful to implement policies for control and prevention of human risk infection.

Human Exposure to Hantaviruses Associated with Rodents of the Murinae Subfamily, Madagascar

“…The overall conservative prevalence estimate of 2.7% from the national-scale study, obtained using 2 ELISA assays, is similar to results from studies in some Africa countries where other confirmatory tests were used (3.9% in Cote d'Ivoire and 2.4% in the Democratic Republic of the Congo) (4,13). Although we believe some seropositive persons may have been exposed to other Murinae-associated hantaviruses, considering both ELISA results in humans and rodent infection data together (7), our observations are consistent with evidence that most were exposed to ANJZV. Specifically, the ANJZV ELISA detected more seropositive persons than the commercial kit, and the cosmopolitan Seoul virus, if present in rodents in Madagascar, is at low prevalence or patchily distributed (7).…”

“…Seropositive participants came from 20 of the 28 study sites (0-13.3% per site) distributed all over Madagascar (Table 1; Figure). Univariate generalized linear mixed models with site-zone as random effect indicated no effect of age, sex, or location (urban or rural), but we did find a slight suggestion of increased exposure in sites where our previous study (7) had detected infected rats (OR 3.0, 95% CI 0.78-11.5; p = 0.11).…”

“…Of interest, when we tested R. rattus rats from the 4 Moramanga sites by nested reverse transcription PCR using a protocol described previously (Appendix) (7), we also observed significantly higher infection rates than those for the national study sites; 77 of 237 rat samples were positive (32.5%; 95% CI 26. χ 2 1 = 5.55; p = 0.02). These results further confirm a relatively high infection rate in the most abundant and widespread rodent in Madagascar.…”

Synanthropic rodents as virus reservoirs and transmitters

“…For example, in an urban area in Salvador, Brazil, Seoul virus antibodies were found in R. norvegicus serum samples 81 . A molecular survey conducted in Madagascar detected the Anjozorobe virus (Thailand Orthohantavirus) strain in R. rattus and M. musculus, suggesting viral spillover 82 .…”

Systematic Review of Important Viral Diseases in Africa in Light of the ‘One Health’ Concept

“…A total of 1242 samples were collected from 7 representative species of rodents found in Madagascar. A total of 111/897 samples (12.4%) of Rattus rattus species and 2 out of 125 (1.6%) samples of Mus musculus species of rodents were found to be positive with nested PCR for the infection of Anjozorobe virus [55]. The study suggested a high zoonotic transmission risk to the human population living in households given the prevalence of Anjozorobe virus in household-dwelling rodent species [55].…”