Seroprevalence of peste des petits ruminants among domestic small and large ruminants in the semi-arid region of north-eastern Nigeria

Expansion in host dynamics of peste des petits ruminants: Potential attribute of outbreaks in disease-endemic settings

Since the first case report in 1942, the peste-des-petits-ruminants virus (PPRV) has been causing infection in a wide range of susceptible hosts, particularly in disease-endemic regions. In the last 40 years, various reports highlighted the evidence of disease and viral genome in around 46 animal species from nine diverse families, including Bovidae, Cervidae, Camelidae, Suidae, Canidae, Felidae, Muridae, and Elephantidae. This evidence of clinical and/ or subclinical infection and the presence of the virus in an extended range of susceptible hosts emphasizes the cross-species transmission that remains a significant obstacle to effective control, particularly in disease-endemic regions. Therefore, a better understanding of virus transmission, host susceptibility, and epidemiological investigation of the disease is crucial to achieving the goals of efficient disease control and eradication programs initiated by OIE and FAO in various diseases-endemic regions. Nevertheless, the propensity of PPRV to inter- and intra-transmission may be a possible constraint in disease control strategies in terms of the new outbreak with the involvement of unusual or novel hosts. Considering this aspect, we tried to summarize the scattered data on PPR in available information about the susceptibility of a wide range of wildlife species, large ruminants, camels, and unusual hosts.

Epidemiology of Peste des Petits Ruminants in Nigeria: A Review

Peste des petits ruminants (PPR) is a major constraint to the productivity of small ruminants in Nigeria. Understanding of the current epidemiological status of PPR is crucial to its effective control. A review of the epidemiology of PPR in Nigeria was performed and research gaps were identified. Thirty-seven eligible articles were reviewed: these presented information from 30 of the 36 states of Nigeria. Most studies focused on goats and/or sheep (n = 33) but camels (n = 4), cattle (n = 1) and wild ruminants (n = 2) were also considered. Fourteen (37.8%) of the articles reported seroprevalence in small ruminants, which varied from 0.0% to 77.5% where more than 10 animals were sampled. Molecular characterization and phylogenetic analysis were performed in 6 studies, with lineages II and IV, detected in sheep and goats. In one study in small ruminants, sequences clustering into lineage I showed a similarity to the vaccine strain, Nigeria 75/1, based on phylogenetic analysis of F gene sequences. However, if the preferred method of sequencing the N gene had been performed, this isolate would have been grouped into lineage II. According to N gene phylogenetic analysis in the other studies, sequences were identified that clustered with clade II-NigA, II-NigB (closely related to the Nigeria 75/1 vaccine strain), and others which were well separated, suggesting a high diversity of PPRV in Nigeria. Five articles reported the detection of lineage IV in 22/36 states, with IV-NigA and IV-NigB detected, highlighting its widespread distribution in Nigeria. Risk factors for PPRV seropositivity were reported in 10/37 (27.0%) articles, with a higher seroprevalence observed in female animals, although differing results were observed when considering species and age separately. There were inconsistencies in study design and data reporting between studies which precluded conduct of a meta-analysis. Nevertheless, several research gaps were identified including the need to investigate the low uptake of PPRV vaccine, and the economic benefits of PPR control measures to small ruminant farmers. Such data will inform PPR control strategies in Nigeria and subsequently contribute to the global 2030 PPR eradication strategy.

Field survey of major infectious and reproductive diseases responsible for mortality and productivity losses of ruminants amongst Nigerian Fulani pastoralists

Background: Animal disease constitutes a major hurdle to improved livelihoods in rural Nigeria through the challenges of loss of productivity, livestock morbidity and mortality including reproductive losses. In order to design and implement impactful interventions, baseline data on the causes of such losses are needed. Therefore, the objective of the present study was to carry out targeted field surveys, including interviews with ruminant farmers, veterinary professionals and other stakeholders in livestock farming to establish the main causes of disease and mortality including abortions in cattle and small ruminants (SR). Methods: Northern Nigeria was selected because the majority of the nation's ruminants belong to pastoralists who are primarily resident in this region. Seven states; Bauchi, Kaduna, Kano, Nasarawa, Niger, Sokoto and Zamfara states were surveyed. The responses were collated and a comprehensive descriptive analysis was carried out. Results: Average cattle herd sizes ranged from 28 in Zamfara to 103 in Nasarawa; and from 27 in Kano to 128 in Sokoto for SR. In cattle, Trypanosomosis (with 4.27% mortality rate), foot and mouth disease (3.81%), nutritional insufficiency (1.93%) and contagious bovine pleuropneumonia (CBPP; 1.44%) were the top four diseases/health problems that resulted in the highest mortality due to diseases within each state surveyed. For SR, trypanosomosis (with 6.85% mortality rate), Peste des Petits Ruminants (4.99%), orf (3.06%), foot rot (2.97%) and foot and mouth disease (2.94%) were the most important diseases responsible for the highest number of mortalities and culling for disease. Conclusions: The study revealed that there are significant losses via mortalities due to the occurrence of disease amongst the ruminant populations countrywide, as evidenced by the high overall mortality rates of both cattle (15.3%) and small ruminants (30.9%) from various diseases. Also, reproductive losses of 8.7% and 16.6% in cattle and SR, respectively, were recorded amongst the farmers involved.

Serological investigations of Peste des Petits Ruminants in cattle of Nepal

Peste des Petits Ruminant (PPR) is an infectious viral disease of small ruminants caused by PPR virus. Although goat and sheep are the primary hosts of PPR, studies have continuously reported the prevalence of circulating antibodies in large ruminants, which could bring a potential challenge to effectively control and eradicate PPR. In Nepal, seroprevalence of PPRV antibodies in cattle have not been monitored yet. To address this, a total of 255 cattle sera were collected from Rupandehi, Banke, Bara and Chitwan districts of Nepal where outbreak of PPR in small ruminants was reported previously. The sera samples were tested by competitive ELISA and the result indicated the prevalence of 5.88% PPRV antibodies in cattle which indicates the exposure of cattle to PPR virus. To make the disease control program effective, intensive monitoring of both domestic and wild animals is very important.

Update on Peste des petits ruminants status in South East Nigeria: serological and farmers' awareness investigation, and potential risk factors

Peste des petits ruminants (PPR) is a highly contagious, trans-boundary viral disease of sheep and goats that have hindered successful small ruminant farming. Its current status in South East Nigeria with respect to its prevalence and farmers' awareness was studied. Three states, Anambra, Ebonyi, and Enugu, were randomly selected for the study. Sera samples from 113 goats and 172 sheep (collected from December 2017 to June 2018) were randomly collected and analysed for the presence of PPRV antibodies, while structured interview schedules were conducted to elicit information on farmers' awareness of the disease and PPR vaccination and use of veterinary services. An overall seroprevalence of 42.5% (121/285) was recorded. The seroprevalence in decreasing order was 62.2% (Enugu), 34.8% (Anambra) and 20.3% (Ebonyi). There was a significant association (X² = 36.08, df = 2, p = 0.0001) between seroprevalence and the state sampled. Lack of awareness of PPR vaccination among small ruminant farmers, their limited use of veterinary services (38% consult veterinarians) and non-availability of the vaccine at veterinary establishments in the sampled states are potential risk factors of PPR prevalence in South East Nigeria. Consequently, an effective control measure like mass vaccination is recommended for the study area. Also, there is a need for an extension program for stakeholders and farmers in the study area and country on the grave importance and economic benefits of PPR vaccination and the use of veterinary services.

Peste des petits ruminants (PPR) in Africa and Asia: A systematic review and meta-analysis of the prevalence in sheep and goats between 1969 and 2018

BACKGROUND

Peste des petits ruminants (PPR) is a prevalent viral disease of sheep and goats that impacts productivity and international animal trade. Despite the substantial economic consequences related to PPR, little is known about the prevalence of this disease at the broad geographical levels.

OBJECTIVE

The present study aimed to use a systematic approach to assess the regional prevalence of PPR in sheep and goats, and the associated factors that contribute to prevalence estimates.

METHODS

Published articles on PPR in sheep and goats were searched in PubMed, Web of Science, Scopus, Google Scholar and the reference lists of articles reporting the prevalence from 1 January 1969 to 31 December 2018. Articles were selected using inclusion and exclusion criteria. Since the heterogeneity among the studies was significant, pooled prevalences were estimated by a random effect meta-analysis model.

RESULTS

Data on the prevalence of PPR were obtained from Africa and Asia, where the pooled prevalence estimates were 40.99% (95% CI: 37.20%-44.79%) and 38.43% (95% CI: 35.64%-41.22%) respectively. Overall, the estimated pooled prevalence at Africa-Asia level in sheep was 39.31% (95% CI: 35.75%-42.88%) and in goats was 39.57% (95% CI: 36.66%-42.48%). Significant heterogeneity (I²  > 80%) was noted in most pooled estimates.

CONCLUSION

The results on the regional prevalence estimates of PPR presented here will be useful in raising awareness and advocating for Governments to engage in initiatives to eradicate PPR and prevent it from spreading to other continents.

Peste des petits ruminants in large ruminants, camels and unusual hosts

Since its first report in 1942, peste-des-petits-ruminants virus (PPRV) has caused several epidemics in a wide range of susceptible hosts around the world. In the last 30 years, the evidence of natural and experimental infections and virus isolation were reported from novel but unusual hosts such as camel, cattle, buffalo, dogs, Asiatic lion and pigs. In addition, PPRV in a potential vector, biting midges (Culicoides imicola), has been reported. Either presented as clinical and/or subclinical infections, the presence of the virus in an extended range of susceptible hosts highlights the cross-species transmission and supports the hypothesis of an endemic circulation of PPRV among susceptible hosts. However, the potential role of large ruminants, camels and unusual hosts for PPRV epidemiology is still obscure. Therefore, there is a need for molecular and epidemiological investigations of the disease among usual and unusual hosts to achieve the goals of disease control and eradication programmes initiated by national and international organisations, such as the FAO and OIE. This review is the first to summarise the scattered data on PPR in large ruminants, camels and unusual hosts to obtain the global scientific communities' attention for further research on epidemiological aspects, not only in its native hosts, but also in large ruminants, camels and other unusual hosts.

Assessment of the peste des petits ruminants world epizootic situation and estimate its spreading to Russia

Aim:

This study focuses on the spatial dynamic associated with the spreading of the peste des petits ruminants (PPR) disease for the past decade (from the year 2007 to 2017), assesses the resulting situation in the world, and has an emphasis on Russian advantages been a PPR host.

Materials and Methods:

Outbreaks were confirmed and reported officially by the World Organization for Animal Health (enzyme-linked immunosorbent assay and polymerase chain reaction were used). Data contain the account number of infected, dead, and all susceptible animals in focus of infection in the period of 2007-2017. Once conventional statistical population was defined, a model was installed. Geo-information system QuickMAP was used to clear up the map disease, and through the ^@Risk program, we got our forecasting value of future situations (by Monte Carlo method).

Results:

The spatial study of PPR’s occurrence and its spread was mapping according to the incidence of cases and outbreaks. Clusters demonstrated risk levels in the world in the period from 2007 to 2017 year. Based on the epizootological analysis, an assessment of PPR risk and the probability movement of infection in Russia from nearby disadvantaged countries had been carried out. A statistically significant impact of the socioeconomic system on the stationarity index was found equal to 0.63. The PPR risk of spreading could not be ignored. Nevertheless, conducting effective large-scale vaccine companies in a complex of antiepizootic activities against PPR could reduce the risk of spread of the disease up to 91.8%.

Conclusion:

Despite all mentioned facts above, the PPR probability can only be reduced by coordinating work of border veterinary services, as in disadvantaged as in free from this disease country, that is, what makes an effective and complete eradication of the disease could be quite realistic.

Serological Investigation of Peste Des Petits Ruminants in East Shewa and Arsi Zones, Oromia Region, Ethiopia

Peste des petits ruminant (PPR) is an economically important disease of small ruminants with a rapidly expanding geographical distribution. There are fragmented reports to the occurrence and distribution of the disease in Ethiopia. A total of 700 serum samples were collected from goats and sheep to detect the presence of antibody against PPR virus using Competitive Enzyme-Linked Immunosorbent Assay (C-ELISA). An overall PPR seropositivity was reported to be 48.43% in the area. There is no statistically significant difference in the seroprevalence of the disease between sheep and goats (50.85% and 46.68%), respectively. However, there was statistically significant variation (P < 0.05) in the seroprevalence of the disease in young (33.9%) and adult (55.8%) age categories. The seroprevalence in male and female was 42.07% and 50.09%, respectively, where the variation was statistically not significant (P > 0.05). High seroprevalence of Peste des petites ruminants in the study area indicated the virus circulation and endemicity of the disease. The disease causes substantial economic losses by affecting the livelihood of the farmers. Therefore, control measures should be put in place to minimize the loss associated with the disease.

Peste des petits ruminants infection in domestic ruminants in Sudan

The existence of peste des petits ruminants (PPR) in domestic ruminants and camels in Sudan during 2008-2012 was investigated. Lung tissues and serum samples were randomly collected from sheep, goats, cattle, and camels at different areas of Sudan. A total of 12,384 serum samples were collected from clinically healthy 7413 sheep, 1988 camels, 1501 cattle, 1459 goats, and 23 gazelles at different areas in the Sudan. They were examined for PPR antibodies using competitive ELISA (cELISA). The overall detected seroprevalence of PPR in tested sera was 49.4%; seroprevalence values within species were 67.1, 48.2, 25.8, 2.1, and 21.7% in sheep, goat, cattle, camels, and gazelles, respectively. The highest seroprevalence (68.1%) was observed in sera collected from Darfur states, then the central states (54.3%). A total of 1276 lung tissue samples (623 sheep, 324 cattle, 220 camels, and 109 goats) were collected. The majority of lung samples were collected from clinically healthy animals that showed lesions on PM in slaughterhouses (95%) and during PPR outbreaks; samples were tested for PPR antigen using immunocapture ELISA (IcELISA). PPR antigen was detected in 233 out of the 1276 tested samples (18.3%). Positive results were observed in samples collected from clinically healthy and diseased animals. The observed prevalence values in each species were 33.6, 21.1, 15.4, and 12.3% in camel, goat, sheep, and cattle, respectively. PPR antigen was detected in samples from different areas; however, the highest prevalence (63.9%) was found in samples collected from the eastern states, then Khartoum state (28%). Trials for virus isolation were done in different cell cultures. Out of 30 IcELISA-positive samples inoculated in primary bovine and ovine kidney cells, Vero cells, the PPR virus was successfully isolated from 15 (eight sheep, five camels, and two goats) samples in the three cell culture types. Using RT-PCR, PPRV nucleic acid was detected in all 25 IcELISA-positive tested samples.

Modelling the Dynamics of Post-Vaccination Immunity Rate in a Population of Sahelian Sheep after a Vaccination Campaign against Peste des Petits Ruminants Virus

Background

Peste des petits ruminants (PPR) is an acute infectious viral disease affecting domestic small ruminants (sheep and goats) and some wild ruminant species in Africa, the Middle East and Asia. A global PPR control strategy based on mass vaccination—in regions where PPR is endemic—was recently designed and launched by international organizations. Sahelian Africa is one of the most challenging endemic regions for PPR control. Indeed, strong seasonal and annual variations in mating, mortality and offtake rates result in a complex population dynamics which might in turn alter the population post-vaccination immunity rate (PIR), and thus be important to consider for the implementation of vaccination campaigns.

Methods

In a context of preventive vaccination in epidemiological units without PPR virus transmission, we developed a predictive, dynamic model based on a seasonal matrix population model to simulate PIR dynamics. This model was mostly calibrated with demographic and epidemiological parameters estimated from a long-term follow-up survey of small ruminant herds. We used it to simulate the PIR dynamics following a single PPR vaccination campaign in a Sahelian sheep population, and to assess the effects of (i) changes in offtake rate related to the Tabaski (a Muslim feast following the lunar calendar), and (ii) the date of implementation of the vaccination campaigns.

Results

The persistence of PIR was not influenced by the Tabaski date. Decreasing the vaccination coverage from 100 to 80% had limited effects on PIR. However, lower vaccination coverage did not provide sufficient immunity rates (PIR < 70%). As a trade-off between model predictions and other considerations like animal physiological status, and suitability for livestock farmers, we would suggest to implement vaccination campaigns in September-October. This model is a first step towards better decision support for animal health authorities. It might be adapted to other species, livestock farming systems or diseases.