Search

Newcastle disease (ND) is among the most important poultry diseases worldwide. It is the major threat to poultry production in Africa and causes major economic losses for both local and commercial chickens. To date, half of ND class II genotypes have been reported in Africa (I, IV, V, VI, VII, XI, XIII, XIV, XVII, XVIII, and XXI). The information on the circulating NDV genotypes is still scarce despite the endemic nature of ND in most countries on the African continent.A total of 659 oro-cloacal swabs were collected from local chickens in Mawenzi live bird market located in Morogoro, Tanzania, between June 2020 and May 2021. Newcastle disease virus was detected by using reverse transcription real-time polymerase chain reaction (RT-qPCR) and conventional PCR followed by sequencing of PCR products. The prevalence of NDV in the surveilled live bird markets was 23.5%. Sequencing and phylogenetic analysis revealed the presence of sub-genotype VII.2. The detected sub-genotype VII.2 has phylogenetic links to Zambian NDV strains implying a Southeast dissemination of the virus, considering that it was first detected in Mozambique. This study underscores the need of active NDV surveillance to determine the distribution of this NDV genotype in the country and monitor its spread and contribution to the emergence of new ND viruses.

Lumpy skin disease (LSD) is an infectious disease of cattle caused by lumpy skin disease virus (LSDV), which is a member of the Poxviridae family and genus Capripoxvirus. The illness is marked by mild to severe symptoms, including edema, fever, lymphadenitis, widespread skin nodules, and infrequently, death. In spite of its significance, little is now understood about the magnitude and predisposing factors in Tanzania. The aim of this study was to determine the seroprevalence of LSD in cattle within Kilolo district, and to identify key predisposing factors. A cross-sectional study was conducted in 17 villages within Kilolo district from February to March 2024 to estimate the seroprevalence of LSD in cattle. A total number of 276 serum samples was obtained from 65 cattle herds and a Double Antigen ELISA (ID Screen®) (IDVet, France) was used to screen for LSDV antibodies. Logistic regression analysis was employed to assess the risk factors for LSD seropositivity. The overall animal- and herd-level seroprevalence were 18.1% (95% CI: 13.98-23.14) and 44.6% (95% CI: 7.54-15.38), respectively. The highest individual animal level seroprevalence was documented in Irindi village 39.1% (95% CI: 5.36-12.24), followed by Masalali 38.5% (95% CI: 6.25-13.50), Ng'uruhe 37.5% (95% CI: 5.65-12.66), Irole 33% (95% CI: 1.5-6.10), and Utengule 26.5% (95% CI: 3.07-8.81) with significant differences (p=0.003). The seroprevalence of LSD varied significantly (P<0.001) among the three age groups, with adults >2 years having a higher seroprevalence (29.8%, 95%CI, 52.27-64.21) than yearlings aged 1-2 years (5. 6%, 95%CI, 9.31-17.60) and calves (0.0%, 95%CI, 23.36-34.35). Sex (Female/male, OR=2.0937, 95%CI, 1.4642-3.0248), age (Yearling/Adult, OR=0.1756, 95%CI, 0.0841-0.3730), village (OR=0.8970, 95%CI, 0.8349-0.9636) and herd size (Large/small, OR=1.9464, 95%CI, 1.1597-3.2669) were significant risk factors for LSDV seropositivity in Kilolo district. Raising awareness among livestock owners and veterinary staff about the disease and its risk factors, vaccination and vector control measures should be prioritized to minimize the transmission of the disease. [ABSTRACT FROM AUTHOR]

Rift Valley fever (RVF), a mosquito-borne transboundary zoonosis, was first confirmed in Rwanda's livestock in 2012 and since then sporadic cases have been reported almost every year. In 2018, the country experienced its first large outbreak, which was followed by a second one in 2022. To determine the circulating virus lineages and their ancestral origin, two genome sequences from the 2018 outbreak, and thirty-six, forty-one, and thirty-eight sequences of small (S), medium (M), and large (L) genome segments, respectively, from the 2022 outbreak were generated. All of the samples from the 2022 outbreak were collected from slaughterhouses. Both maximum likelihood and Bayesian-based phylogenetic analyses were performed. The findings showed that RVF viruses belonging to a single lineage, C, were circulating during the two outbreaks, and shared a recent common ancestor with RVF viruses isolated in Uganda between 2016 and 2019, and were also linked to the 2006/2007 largest East Africa RVF outbreak reported in Kenya, Tanzania, and Somalia. Alongside the wild-type viruses, genetic evidence of the RVFV Clone 13 vaccine strain was found in slaughterhouse animals, demonstrating a possible occupational risk of exposure with unknown outcome for people working in meat-related industry. These results provide additional evidence of the ongoing wide spread of RVFV lineage C in Africa and emphasize the need for an effective national and international One Health-based collaborative approach in responding to RVF emergencies. [ABSTRACT FROM AUTHOR]

Village poultry plays a vital role in providing essential nutrition and income for rural communities in Africa. In this context, poultry are often traded through live bird markets (LBMs), which serve as central trading hubs where producers connect with traders and consumers, facilitating the flow of poultry products along the value chain. While they serve as important trading hubs, these markets create an environment where avian pathogens, like Newcastle disease virus (NDV) and avian influenza virus, can easily emerge and spread. Improving our understanding of the epidemiology of NDV in LBMs is important for assessing disease risks and identifying factors that contribute to its persistence. Local chickens at the Mawenzi LBM in Morogoro municipality were surveyed for NDV presence, its temporal and spatial distribution, and risk factors for NDV infection. Twenty-three percent of 659 local chickens sampled over a 1-year period were positive for NDV based on PCR. Increased odds of NDV infection were identified in chickens that had been in the market for 2 or more days prior to sampling and during the period extending from August through October. Four significant spatiotemporal clusters of NDV-positive chickens encompassing 13 villages were detected between August and October 2020, illustrating geographic hotspots of infection when NDV was most prevalent. Similar to the other LBMs, this market had enclosures with high densities of birds of mixed species, limited biosecurity, and the presence of birds with observable illness. Bird traders who source the chickens from the villages, described long transit times in mixed enclosures with limited sanitation practices and without consideration of sick birds or vaccination status prior to arriving at the LBM. This study highlights the need to invest in improvements to infrastructure and biosecurity for LBMs as well as training opportunities for increasing traders' knowledge on hygiene and sanitation practices, animal welfare, and poultry biosecurity measures. [ABSTRACT FROM AUTHOR]

Babesia species are protozoan parasites that parasitize the erythrocytes of domestic animals and humans, causing anemia in the host. The parasites cause a zoonotic disease known as babesiosis. Polymerase chain reaction (PCR) has proven to be very sensitive for detecting Babesia in blood samples of affected animals, particular in ruminants. The purpose of the current study was to determine the presence of Babesia spp. in blood samples obtained from 2 cattle, camel and sheep in Iran. In addition, the study aimed at establishing a rapid, reliable, specific and sensitive molecular tool, the polymerase chain reaction (PCR), for the detection of Babesia spp. in ruminants. Blood samples were collected from 372 ruminants (155 cattle, 95 sheep and 122 camel) kept at the Livestock Experimental Station. The animals came from randomly selected herds located in the important livestock-production regions of Iran of Isfahan and Chaharmahal va Bakhtiary during December 2012 to March 2013. PCR was used to detect Babesia spp. in the blood samples whereby an amplified band size of 428 bp was considered positive for Babesia spp. The results show that 7.10% (n= 155), 6.56% (n= 122) and 0.00% (n= 95) of the blood samples from cattle, camel and sheep, respectively, were positive for Babesia spp.. The findings from this study revealed that there were Babesia spp. in blood taken from cattle and camel. To our knowledge, this is the first report to show the presence of Babesia spp. in blood samples of Iranian ruminants in Chaharmahal Va Bakhtiari and Isfahan provinces by PCR. These findings justify the importance of control of and eradication plans for Babesia spp. infection in cattle and camel in Iran. As diagnosis of low-level infections by the parasite is important for epidemiological studies, our findings support the power of PCR test for Babesia spp. detection in blood samples and could be easily used for routine diagnosis.

Background: Poultry farmers need different information in order to improve their farming and contribute to the national economy. Information on poultry management is usually obtained from family members, friends, and neighbors with previous experience, extension officers, researchers, Television, radio, web and mobile based agriculture information systems. Promoting utilisation of vetted sources of information is envisaged to support poultry farmers in making informed decisions about management practices. This in turn will result into increased poultry productivity. Objective: Many researches have been done to evaluate various information sources but few have been done to evaluate the mobile based extension, advisory and learning system here referred to “UshauriKilimo". This study particularly assessed poultry farmers' information needs and extension advices given through the agro-advisory system among farmers in Kilosa district of Tanzania. The objective was to determine poultry farmers' information needs submitted through “UshauriKilimo" and resulting advisory responses. Method: ICT based agro-advisory system 'UshauriKilimo' was deployed and used by poutry famrers for more than two years. The data from it were used to assess poultry farmers information needs. Only questions and advisory responses addressing poultry farming were analysed. These data were imported into the Qualitative Data Analysis Software, MAXQDA Plus 12 (Release 12.2.0) where they were coded, counted and analysed. Frequencies of variables were performed during content analysis. Results: More than 340 farmers used “UshauriKilimo" for the period of two years. There were more than 1500 questions and answers which contained 320 questions related to poultry farming. Most of the poultry farmers who used “UshauriKilimo" sought information on health management aspects (diseases transmission, diagnosis, treatment and control); egg production; chicken feeds and feeding; chicken breeds and housing aspects. Information on markets was the least used. [ABSTRACT FROM AUTHOR]

Newcastle disease virus (NDV) is an extremely contagious and deadly virus that affects numerous bird species, posing serious threats to poultry production on a global scale. In addition to implementing biosecurity practices in farming systems, vaccination remains the most effective means of controlling Newcastle disease (ND). However, while existing commercial vaccines provide some level of protection, the effectiveness of these vaccines can be questionable, particularly in field settings where the complexity of vaccination program implementation poses significant challenges, especially against virulent genotypes of NDV. A genotype-matched NDV DNA vaccine could potentially offer a more effective vaccination approach than currently available live attenuated vaccines. By being specifically tailored to match circulating strains, such a vaccine might improve efficacy and reduce the risk of vaccine failure due to genotype mismatch. To develop an alternative vaccine approach, two ND DNA vaccines were constructed in this study. Each vaccine developed in this study contains the fusion (F) and haemagglutinin-neuraminidase (HN) genes of a virulent NDV genotype VII isolate from Tanzania. Interferon lambda-3 (IFNλ3; IL-28b), which has demonstrated capacity to significantly enhance specific adaptive immune responses and decreased levels of inflammatory cytokines, as well as improved protective responses at a high viral challenge dose, was included in one of the developed vaccines. These plasmids were designated pTwist-F-HN-VII-IL28b and pTwist-F-HN-VII. The two plasmids differed in that pTwist-F-HN-VII-IL28b contained the cytokine adjuvant IL-28b. Transfection of cells and subsequent immunofluorescence assays indicated that both plasmids expressed high levels of NDV F-HN proteins. In vivo immunization demonstrated that chicks intramuscularly immunized with pTwist-F-HN-VII-IL28b exhibited significant immune responses compared to chicks immunized with pTwist-F-HN-VII or the commonly used LaSota vaccine (LaSota), which was used as a control. The protective efficacy of pTwist-F-HN-VII-IL28b was 80% after challenge with the highly virulent NDV strain ON148423, compared to 60% for chicks vaccinated using LaSota, and pTwist-F-HN-VII. The findings of this study indicate that IL-28b can be employed as a molecular adjuvant for NDV vaccines. This study represents a key milestone in Newcastle disease vaccine research, particularly in the development of a genotype-matched DNA vaccine candidate. Additionally, this study demonstrated that the combination of F, HN, and IL-28b elicits an efficacious immune response against virulent NDV strains., Competing Interests: Declarations. Institutional review board: For the vaccine development and in vitro testing, this study was carried out according to the recommendations in the Guide for the Care and Use of Laboratory Animals of the National Institutes of Health. The Institutional Biosafety Committee of Virginia Tech approved the research for the ND DNA vaccine. For the vaccine experimentation on animals, ethical clearance was obtained from the Office of the Vice-Chancellor, Sokoine University of Agriculture, Tanzania and Permission to undertake animal health research in Tanzania from the United Republic of Tanzania Ministry of Livestock and Fisheries (Ref. No. DB.16/324/01/137). Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

The emergence of new virulent genotypes and the continued genetic drift of Newcastle disease virus (NDV) implies that distinct genotypes of NDV are simultaneously evolving in different geographic locations across the globe, including throughout Africa, where NDV is an important veterinary pathogen. Expanding the genomic diversity of NDV increases the possibility of diagnostic and vaccine failures. In this review, we systematically analyzed the genetic diversity of NDV genotypes in Africa using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Information published between 1999 and 2022 were used to obtain the genetic background of different genotypes of NDV and their geographic distributions in Africa. The following genotypes were reported in Africa: I, II, III, IV, V, VI, VII, VIII, XI, XIII, XIV, XVII, XVIII, XX, and XXI. A new putative genotype has been detected in the Democratic Republic of the Congo. However, of 54 African countries, only 26 countries regularly report information on NDV outbreaks, suggesting that this number may be vastly underestimated. With eight different genotypes, Nigeria is the country with the greatest genotypic diversity of NDV among African countries. Genotype VII is the most prevalent group of NDV in Africa, which was reported in 15 countries. A phylogeographic analysis of NDV sequences revealed transboundary transmission of the virus in Eastern Africa, Western and Central Africa, and in Southern Africa. A regional and continental collaboration is recommended for improved NDV risk management in Africa.