Nussieba A. Osman

Multiple outbreaks with high mortality rates and a pattern of disease occurrence similar to peste des petits ruminants (PPR) were observed in sheep and goats across many states of Sudan between 2015 and 2018. Therefore, this study aimed to investigate and identify the cause of these disease outbreaks. A total of 276 blood and lung tissue samples were collected from infected sheep (n = 223) and goats (n = 53). Sample analysis in an IC-ELISA revealed the presence of the PPRV antigen in 56.9% of sheep and 62.3% of goat samples. Twenty-seven [sheep (18) and goats (9)] PPRV-positive samples from IC-ELISA were subsequently confirmed positive using the PPRV N-gene-based RT-PCR. Two PPR viruses were isolated from infected small ruminant lung tissues in Vero cells. The partial N-gene sequences for five PPRV strains originating from sheep and goats were determined. Phylogenetic tree grouped PPRV strains identified in this study in lineage IV in sub-lineage NEA (North–East Africa), with the highest sequence identity observed with strains circulating in North African countries. This study and earlier published phylogenetic analysis and patterns of animal movements suggest that the transboundary transmission of PPRV lineage IV strains between East and North African countries has been happening since 2008 and established a new North–East Africa episystem that needs to be disrupted for the successful global eradication of PPR.

Obtaining a better overview of peste des petits ruminants epidemiology in North-East Africa is critical for guiding the ongoing PPR Global Control and Eradication Strategy. This study demonstrated PPRV exposure and potential endemic circulation among small ruminants through the identification and characterization of PPRV strains in lung tissues from slaughtered SR in Sudan. Lung tissues displaying pneumonia, comprising 83 cases (65 sheep and 18 goats), were collected from slaughterhouses in five Sudanese states. An IC-ELISA screening indicated an overall estimated antigenic prevalence of 24.1%, with a significantly higher prevalence in goats (66.7%) compared to sheep (12.3%). Northern Sudan had the highest antigenic prevalence (80%). PPRV-positive samples, confirmed by IC-ELISA and N-gene-based RT-PCR. Sanger sequencing and phylogenetic analysis of PPRV N-gene fragments assigned Sudanese strains to lineage IV genotype, revealing substantial sequence identity (100–96.58%) with strains from North Africa, East Africa, and Europe. The study suggests subclinical PPRV infections or co-infections with other respiratory pathogens affected slaughtered SR, contributing to the observed lung gross pathology. In summary, the endemic transmission of lineage IV PPRV strains in Sudan highlights the need for intensified PPR control strategies at the national level and serves to inform the Global PPR Control initiative led by WOAH/OIE and FAO.

Information on the circulation of foot‐and‐mouth disease (FMD) in Western Syria is very limited. It is known that the country is affected by a prolonged humanitarian crisis that may certainly have contributed to such lack of information and the latest available data date back to 2002. Since 2021, there has been a significant increase in reporting of FMD clinical cases in dairy cattle in the region that led to implementing a vaccination campaign, using a tetravalent vaccine and targeting 35 subdistricts in the governorates of Aleppo and Idleb. Sampling for postvaccination monitoring was carried out, on average, around 2 months from the date of vaccination. Sera from 886 animals were collected and tested through ELISA tests to detect antibodies against FMD virus nonstructural proteins (NSPs) and structural proteins (SPs). Results revealed the presence of antibodies in 22.6% of the animals, directed towards viral NSP, indicating a previous infection. This was likely due to a rather recent exposure, considering the comparable NSP antibody prevalences among different age groups. Serological analyses revealed a good antibody response to Asia1 serotype following vaccination but an insufficient antibody response to serotypes A and O. Multiple logistic regression of the serological titers obtained for the different serotypes showed a significant association between high titers detected for serotype O and positivity towards the NSP of the virus. This result suggests the recent circulation of serotype O in the area under consideration.

Clinical signs suggestive of peste des petits ruminants (PPR) involved herds of small ruminants, which were described elsewhere in Sudan. Peste des petits ruminants was confirmed using an Immunocapture ELISA (IC-ELISA) assay in samples of infected and dead animals in areas of outbreaks. Therefore, to update information regarding the current situation and for assessment of the serological prevalence of PPR in small ruminants mingled at Central and Western Sudan during 2018–2019, 368 sera were collected from sheep (325 sera) and goats (43 sera) with different ages and breeds. These sera included 186 sera (173 sheep and 13 goats) from White Nile State and 182 sera (152 sheep and 30 goats) from Kordofan States. Competitive ELISA demonstrated higher prevalence of PPRV antibodies of 88.9%, 90.7% and 88.6% in both sheep and goats, goats, and sheep sera, respectively. Moreover, 100%, 94.7% and 78.5% seroprevalence values were demonstrated in South Kordofan, North Kordofan and White Nile States. The higher seroprevalence values detected in sera of unvaccinated sheep and goats indicated the wide exposure of these animals to PPRV and presence of protection following PPR viral infection. The findings of the study indicated that PPR is endemic in the surveyed areas of Sudan.Contribution: The study will contribute effectively to the global eradication programme of PPR organised by the World Organization for Animal Health (WOAH, formerly OIE) and Food and Agriculture Organization (FAO). To completely eliminate PPR from Sudan by 2030, local efforts should be directed towards effectively and wholly vaccinating small ruminants using PPRV vaccine especially in routes of seasonal animal’s movement and shared grazing areas.

Background and Aim: Newcastle disease (ND), a major constraint to poultry production worldwide, is a highly contagious disease of many species of domestic, exotic, and wild birds caused by ND virus (NDV). Epidemiological studies are lacking regarding ND in village chickens, including the traditional and intensive production systems used in Sudan. However, it is necessary to develop appropriate strategies to control the disease. Therefore, this study aimed to estimate the flock-and bird-level seroprevalence of NDV in backyard chickens in West Kordofan State, Sudan, and to identify the risk factors associated with ND in the study area.Materials and Methods: The seroprevalence of the circulating NDV and bird-level risk factors associated with ND was determined in backyard chickens from March to October 2017, in six villages (Alnowara, Alleait, Geibaish, Baiad, Sougoh, and Alnuhoud) in the Geibaish and Elnuhoud localities of West Kordofan State.Results: Using the hemagglutination-inhibition test, the bird-and flock-level seroprevalences of antibodies to NDV were estimated as 20.6% (78/378) and 45% (18/40), respectively. Bird-level NDV seropositivity in backyard chickens was significantly associated with the reason for raising chickens, type of housing, contact with neighboring poultry, contact with wild birds, and chicken mortality caused by infectious diseases (p <= 0.05).Conclusion: This study indicated that NDV is circulating in backyard chickens and may act as a potential source of infection for other birds and thus persistence of ND among local traditionally managed chickens in the areas of West Kordofan State. Risk factors contributing to ND occurrence are important for designing appropriate prevention and control strategies.

A total of 367 bovine sera positive to antibodies against non-structural proteins (NSPs) of foot-and-mouth disease (FMD) virus were screened for serotype O, A and SAT2 antibodies using the virus neutralization test (VNT). Sera had been collected in 2016 from North (228) and South (139) Darfur States in Western Sudan, where high and low circulation of FMD virus, respectively, prevailed. Tested sera represented the positive-NSPs portion in a random sample of 669 sera collected from both States. According to standard statistical methods, calculations for serial testing (NSPs ELISA and VNT) were applied to estimate prevalence rates of serotype-specific antibodies in the two States. In each State, approximately 20% of NSPs positive sera failed typing. Prevalence's detected were 49% ± 5% (O), 27% ± 5% (A) and 14% ± 4% (SAT2) in North Darfur State and 27% ± 5% (O), 17% ± 4% (A) and 8.0% ± 3% (SAT2) in South Darfur State. In both States, prevalence rates were significantly higher for serotype O, followed by A then SAT2; the same order that was known in most parts of Sudan. Consistently, estimated prevalence's were statistically significantly higher (P < 0.05) in North Darfur than in South Darfur State. Apart from serotype SAT2, detected prevalence rates were lower or similar to those inside the country in previous occasions. Frequency and pattern of distribution of serotype O prevalence were consistent with its suggested pattern of circulation from the Nile valley to other parts in Sudan and significant within the country's circulation. Alternatively, serotype SAT2 prevalence and distribution in Darfur area were suggestive of sporadic occurrence. However, slightly higher prevalence rates of SAT2 antibodies in Darfur than in neighbouring Kordofan areas in 2013 reflected the wide dissemination of SAT2 (http://www.wrlfmd.org) in Sudan in early 2014. Risk of FMD in Darfur seemed to be associated with the movement of animals to the North in the wet season as part of the pastoral system, and with movement related to trade into urban centers more than with pastoralism across the Western borders. Generally, the result presented little evidence to suggest presence of FMD primary endemic foci in Darfur area.

A total of 367 bovine sera positive to antibodies against non-structural proteins (NSPs) of foot-and-mouth disease (FMD) virus were screened for serotype O, A and SAT2 antibodies using the virus neutralization test (VNT). Sera had been collected in 2016 from North (228) and South (139) Darfur States in Western Sudan, where high and low circulation of FMD virus, respectively, prevailed. Tested sera represented the positive-NSPs lot in a random sample of 669 sera collected from both States. According to standard statistical methods, calculations for serial testing (NSPs ELISA and VNT) were applied to estimate prevalence rates of serotype specific antibodies in the two States. In each State, around 20% of NSPs positive sera failed typing. Prevalence's detected were 49%±5% (O), 27%±5% (A) and 14%±4% (SAT2) in North Darfur State and 27%±5% (O), 17%±4% (A) and 8.0%±3% (SAT2) in South Darfur State. In both States, prevalence rates were significantly higher for serotype O, followed by A then SAT2; the same order that was known in most parts of Sudan. Consistently, estimated prevalence's were statistically significantly higher (P < 0.05) in North Darfur than in South Darfur State. Apart from serotype SAT2, detected prevalence rates were lower or similar to those inside the country in previous occasions. Frequency and pattern of distribution of serotype O prevalence were consistent with its suggested pattern of circulation from the Nile valley to other parts in Sudan and significant within the country's circulation. Alternatively, serotype SAT2 prevalence and distribution in Darfur area were suggestive of sporadic occurrence. However, slightly higher prevalence rates of SAT2 antibodies in Darfur than in neighbouring Kordofan areas in 2013 reflected the wide dissemination of SAT2 (http://www.wrlfmd.org) in Sudan in early 2014. Risk of FMD in Darfur seemed to be associated with the movement of animals to the North in the wet season as part of the pastoral system, and with movement related to trade into urban centers more than with pastoralism across the Western borders. Generally, the result presented little evidence to suggest presence of FMD primary endemic foci in Darfur area.

The study investigated the presence and prevalence of peste des petits ruminants (PPR) viral antigens among camels in Tambul area, Gezira State, Central Sudan, regardless of its sex, age and breed, and their possible contribution in the epidemiology of the disease in the Sudan. Hundred pneumonic lung tissues were aseptically collected from clinically apparently healthy camels showed no signs of illness at ante‐mortem examination, from Tambul slaughterhouse, Tambul area, Gezira State, Central Sudan, between November and December 2018. Samples were collected based on presence of the pneumonic signs, at the tissue level, including congestion of the lungs, presence of abscesses, fragility, changes in colour and thickness of the tissue. In order to detect PPR viral antigen, haemagglutination (HA) test was employed on lung tissue homogenate, using chicken RBCs suspension, which gave a positive reaction in 17–19 min. PPRV antigen was detected in 98 of camel samples with an overall antigenic prevalence of 98%. Of note, the HA titres achievable ranged from 4 to 256 HA units (HAU) with mean titre of 14.4 HAU, whereas apparently most of the samples achieved HA titres of 8 HAU. The results demonstrated presence of PPR viral antigens associated with pneumonia in camels indicating exposure of these camels to PPRV and probably presence of subclinical infection. Infection of species other than small ruminants suggests the fact that camels are potential hosts for PPRV and might play a role (or not) in the epidemiology of the disease. Further studies are needed to demonstrate if camels are able to transmit PPRV for in‐contact small ruminants or other animal species.

The study aimed to investigate the presence of peste des petits ruminants (PPR) in pneumonic lung tissues from clinically apparently healthy sheep and goats and further demonstrating its prevalence in Gezira state, central Sudan. During March 2019, 99 pneumonic lung samples were collected from apparently healthy sheep (80) and goats (19) from Al-Hasaheisa slaughterhouse located in Al-Hasaheisa locality, Gezira state. Using the haemagglutination (HA) test for the detection of peste des petits ruminants virus (PPRV) antigen, an overall antigenic prevalence of 86.9% was demonstrated in sheep and goats lung tissue homogenate. Of note, the prevalence of PPRV is higher in goats (100%) compared to sheep (83.7%). In this study, the reported increasing prevalence of PPR in central Sudan might be because of insufficient vaccination of animals. The findings of the present study indicated the widespread of PPR amongst sheep and goats in Al-Hasaheisa, Gezira state. Detection of PPRV antigen in the pneumonic lung samples is an indication of exposure of these animals to PPRV or presence of PPR viral infection and demonstrates the role of PPR as the cause of pneumonia in small ruminants. In fact, the circulation of the virus in clinically apparently healthy animals poses a threat for other in-contact susceptible animals and could play a significant role in the spread of the disease.