Serological survey on Hepatitis E virus in Namibian dogs, cats, horses, and donkeys.

The present study investigated the seropositivity rate of Hepatitis E virus (HEV) in domestic and working animals in Namibia, which included dogs, cats, horses, and donkeys. HEV poses a growing threat as a significant cause of human hepatitis globally and has several genotypes of varying zoonotic potential. As epidemiological data on the seroprevalence of HEV in Namibia is scarce, a serosurvey was conducted on archived serum samples of 374 dogs, 238 cats, 98 horses, and 60 donkeys collected between 2018 and 2022 from different regions, to assess the potential of these animals as sources of HEV infection. The findings revealed that 10.43% (n = 39/374) canine and 5.88% (n = 14/238) feline samples tested positive for HEV antibodies, whereas no seropositivity was detected in horses and donkeys. The study further examined the risk factors associated with HEV seropositivity, including animal sex, age, and geographical region, and noted a higher prevalence in dogs living in areas with intensive pig farming. Although there is no direct evidence indicating that these animals served as major reservoirs for HEV transmission to humans, the study underscores the importance of preventive measures to minimize contact exposure with pets considering the potential zoonotic risk, especially for susceptible risk groups. Further research is needed to explore the zoonotic potential of domestic animals and the epidemiological links between animal and human HEV transmissions in Namibia.

Molecular epidemiology of canine parvovirus in Namibia: Introduction pathways and local persistence.

Canine parvovirus is a member of the Carnivore protoparvovirus 1 species that, after a relatively recent origin, has reached a worldwide distribution. Like other ssDNA viruses, it is featured by a remarkable evolutionary rate and thus genetic variability. CPV-2 is responsible for a severe systemic infection affecting especially domestic dogs. However, other carnivores, including wild species, are susceptible and thus represents a menace to wildlife conservation too. Despite the relevance of the topic, molecular epidemiology data are scarce and outdated in certain areas of the world, like Africa and, in particular, Namibia. The present study investigates the occurrence and genetic features of CPV in Namibian domestic dogs and jackals. The VP2 of detected strains was characterized and analyzed to assess the viral circulation and link among host species, Namibian districts and foreign countries. With the only exception of one New-CPV-2a, all the detected strains belonged to the CPV-2c antigenic variant and were closely related to strains of Asian origin. Nevertheless, a dedicated phylogeographic analysis revealed that the introduction was more likely mediated by other African countries, highlighting the challenge of controlling illegal animal imports across land borders. Similarly, the absence of any geographical clustering within Namibia testify a substantially unconstrained viral circulation among districts. The absence/incomplete vaccination status reported by the animal owners could have significantly contributed to the infection's success after its introduction. Finally, infection of a wild jackal was also proven. Although the limited wild animals' sample size prevents any definitive conclusion, the identity of the sequences from the jackal and the ones originating from the domestic dogs suggests a potential inter-species transmission. The epidemiological and clinical implications in wild specie remain obscure.

Molecular Detection and Genetic Characterization of Porcine Circovirus 2 (PCV-2) in Black-Backed Jackal (Lupulella mesomelas) in Namibia.

Members of the genus Circovirus have been identified in several host species. While initially considered host-specific, there is growing evidence of their presence in unexpected hosts. Porcine circovirus 2 (PCV-2) is no exception, having been reported in animals belonging to different orders, including carnivores. Recently, PCV-2 was detected in domestic pigs, warthogs and antelopes in Namibia. Considering the potential contact between these populations and wild carnivores, the presence of PCV-2 was investigated in 32 black-backed jackals (Lupulella mesomelas) shot between February and July 2021 as part of predator control operations in Namibia. Two lung lymph nodes tested positive for PCV-2 by PCR, confirming the broader-than-expected PCV-2 host tropism and the susceptibility of canids. Sequence analysis demonstrated a close association between the PCV-2s identified in the jackals and PCV-2b strains collected from South African domestic pigs. Although several hypotheses regarding the source of the jackal's infection are proposed, further studies should be performed to properly assess how PCV-2 is acquired and maintained in the wild and its potential impact on wild and domestic species.