Molecular, antigenic, and pathogenic characterization of H5N8 highly pathogenic avian influenza viruses isolated in the Democratic Republic of Congo in 2017.

In May 2017, high mortality of chickens and Muscovy ducks due to the H5N8 highly pathogenic avian influenza virus (HPAIV) was reported in the Democratic Republic of Congo (DR Congo). In this study, we assessed the molecular, antigenic, and pathogenic features in poultry of the H5N8 HPAIV from the 2017 Congolese outbreaks. Phylogenetic analysis of the eight viral gene segments revealed that all 12 DR Congo isolates clustered in clade 2.3.4.4B together with other H5N8 HPAIVs isolated in Africa and Eurasia, suggesting a possible common origin of these viruses. Antigenically, a slight difference was observed between the Congolese isolates and a representative virus from group C in the same clade. After intranasal inoculation with a representative DR Congo virus, high pathogenicity was observed in chickens and Muscovy ducks but not in Pekin ducks. Viral replication was higher in chickens than in Muscovy duck and Pekin duck organs; however, neurotropism was pronounced in Muscovy ducks. Our data confirmed the high pathogenicity of the DR Congo virus in chickens and Muscovy ducks, as observed in the field. National awareness and strengthening surveillance in the region are needed to better control HPAIVs.

Seroprevalence of Rift Valley fever virus in cattle in the Democratic Republic of the Congo.

This study aimed at assessing the serological and virological status of Rift Valley fever virus (RVFV) in cattle from four climatically diverse zones of the Democratic Republic of the Congo (DRC). A total of 1675 sera samples collected between 2014 and 2015 from cattle without clinical manifestation of RVF infection were tested using competitive and capture enzyme ELISA to detect both IgG and IgM. RT-PCR was used for the detection of nucleic acid of RVFV. Out of the 1675 cattle sera tested, 203 were found to be IgG-positive, giving an overall true seroprevalence of 12.37% (95% CI 10.86-14.05). This seroprevalence varied between the four zones with a seroprevalence of 16.16% (95% CI 12.86-20.12), 14.70% (95% CI 11.72-18.29), 10.82% (95% CI 7.19-14.19), and 7.34% (95% CI 5.13-10.41) recorded in cattle sampled in the mountainous, humid savannah, dry savannah, and forest zones, respectively (p < 0.05, χ2 = 17.26). A higher true seroprevalence of 14.58% (95% CI 9.3-22.13) was found in animals aged 1 year compared to 10.43% (95% CI 8.12-13.30) and 13.16% (95% CI 11.19-15.42) in groups aged between 2-3 and > 3 years, respectively, although the difference was not statistically significant (p > 0.05, χ2 = 2.95). Similarly, no statistically significant difference (p > 0.05, χ2 = 0.04) was found between the sexes of the animals. Among the IgG-positive samples screened for anti-RVFV IgM, only 1.47% (3/203) was IgM-positive. One of the IgM-positive samples was positive by RT-PCR. These findings reveal country-wide distribution of RVF in the DRC for the first time.

Peste des petits ruminants viruses of lineages II and III identified in the Democratic Republic of the Congo.

Understanding the molecular epidemiology and evolution of peste des petits ruminants virus (PPRV), the causative agent of Peste des petits ruminants, can assist in the control of the transboundary spread of this economically important disease. To date, despite having been reported in the majority of northern and central African countries, no molecular epidemiological data on PPRVs are available for the Democratic Republic of the Congo (DRC). This study reports the collection and analysis of 11 samples collected from three provinces of the DRC in 2016 and 2018. Sequence analysis identified two (i.e. II and III) of the four known lineages of PPRV in the country providing important information that will assist in the global eradication of PPR.

Determinants of dog owner-charged rabies vaccination in Kinshasa, Democratic Republic of Congo.

Rabies is a preventable fatal disease that causes about 61,000 human deaths annually around the world, mostly in developing countries. In Africa, several studies have shown that vaccination of pets is effective in controlling the disease. An annual vaccination coverage of 70% is recommended by the World Health Organization as a control threshold. The effective control of rabies requires vaccination coverage of owned dogs. Identification of the factors determining dog owners' choice to vaccinate is necessary for evidence-based policy-making. However, for the Democratic Republic of Congo (DRC), the limited data on rabies vaccination coverage makes it difficult for its control and formulation of appropriate policies. A cross-sectional study was conducted in Kinshasa (Lemba commune) with dog-owning households and owned dogs as study populations. The association between dog vaccination and independent factors (household socio-demographics characteristics, dog characteristics, knowledge of rabies and location of veterinary offices/clinics) was performed with Epi-info 7. The Odds Ratio (OR) and p-value < 0.05 were used to determine levels of significance. A total of 166 households owning dogs and 218 owned dogs were investigated. 47% of the dogs had been vaccinated within one year preceding the survey which is higher than the critical coverage (25 to 40%) necessary to interrupt rabies transmission but below the 70% threshold recommended by WHO for control. The determinants of vaccination included socio-economic level of the household (OR = 2.9, p<0.05), formal education level of the dog owner (OR = 4, p<0.05), type of residence (OR = 4.6, p<0.05), knowledge of rabies disease (OR = 8.0, p<0.05), knowledge of location of veterinary offices/clinics (OR = 3.4, p<0.05), dog gender (OR = 1.6, p<0.05) and dog breed (OR = 2.1, p<0.05). This study shows that the vaccination coverage in this area can easily reach the WHO threshold if supplemented by mass vaccination campaigns.