Seromolecular surveillance of rabbit haemorrhagic disease virus in Nigeria

Following the first 2020 rabbit haemorrhagic disease virus (RHDV) outbreak in Nigeria which caused massive mortalities in several rabbitries, there was a need to know the spread and strains circulating in the affected states. Over 100 rabbitries still existing post-RHDV outbreak in Ogun and Kwara States were investigated. A commercial enzyme-linked immunosorbent assay kit was used to screen for RHDV immunoglobulin G in 192 rabbit sera, while RHDV VP60 gene was amplified in RNA extracted from these sera and tissues (liver and/or spleen harvested from 37 carcasses necrotized) by reverse transcription-polymerase chain reaction (RT-PCR). Sequences obtained from the amplicons were subjected to phylogenetic analysis. The results revealed a seroprevalence of 82.3% (158/192). RHDV VP60 gene was detected in 15/17 (88.2%) and 2/20 (10.0%) carcasses from Ogun and Kwara States, respectively, while none of the sera was positive. Sequences of the two positive amplicons selected (one from each states) shared 98.95% nucleotide identity and belonged to RHDV 2/GI.2 strain. Also, nBLAST of these sequences revealed 98.43-99.55% homology with the prototype Nigerian RHDV strain RHDV/NGR/ILN/001 (MT996357.1). Furthermore, these strains clustered with this prototype and a German RHDV strain (LR899166.1). Pathologic lesions affecting the respiratory, cardiovascular, renal, lymphatic, and digestive systems were observed in necropsied carcasses. This study indicated that RHDV 2/GI.2 strain was the cause of 2020 RHD outbreak in Nigeria. Thus, while continuous public sensitization about RHD especially among rabbit farmers in Nigeria is important, efforts aimed at design and implementation of RHD vaccination policy, preferably using indigenous seed, should be expedited.

Epidemiological studies of gastrointestinal parasites infecting dogs in Kwara Central, North Central, Nigeria

Dogs are the most cosmopolitan pets of humans and as such a means of transmitting zoonotic parasites to their owners. This study was designed to investigate the diversity, prevalence, pattern of infection, intensity of infections, and the risk factors associated with gastrointestinal parasites of dogs in Kwara Central, North Central, Nigeria. Three hundred and five clinically healthy dogs were sampled. Faecal samples were subjected to the direct smear, simple faecal centrifugation flotation, formol-ether concentration, and the Modified Ziehl-Neelsen staining techniques. Oocysts/eggs per gram of faeces were counted using the modified McMaster technique. Data were analysed using univariate logistic regression, multivariate logistic regression, and the one-way analysis of variance (ANOVA). A p -value of < 0.05 was considered significant for all analyses. One hundred and sixty-six dogs were positive for at least one species of gastrointestinal parasite, representing 54.43% (95% CI: 44.81 - 59.96) of the sampled population. The study identified Cystoisospora species (15.41%), Cryptosporidium species (25.25%), Ancylostoma species (25.25%), Toxocara canis (19.02%), Strongyloides stercoralis (7.54%), Uncinaria stenocephala (6.89%), and Dipylidium caninum (2.30%) as the gastrointestinal parasites infecting dogs in the study area. Coinfection with more than one species of gastrointestinal parasites was a common finding in dogs. The intensity of Cystoisospora spp. among infected dogs ranged between 40 and 980 oocysts per gram of faeces, while that of helminth parasites was 40 - 1560 eggs per gram of faeces. Age, sex, breeds, body condition score, presence of ticks on dogs, the purpose of keeping dog(s), types of housing, types of feed consumed, vaccination status, and treatment with antiparasitics were predators associated with the prevalence and intensity of gastrointestinal parasites infections. Due to the zoonotic nature of most of the encountered gastrointestinal parasites, there is need for regular antiparasitic treatment, proper dog management, and adequate personal hygiene to prevent zoonosis.

Antidiabetic and antihyperlipidemic effects of aqueous extract of Parquetina nigrescens in streptozotocin-nicotinamide induced type 2 diabetic rats

Background

Parquetina nigrescens is among the evergreen plants native to West Africa. It is used in the management of various ailments including anemia, fever, asthma and diabetes. This study evaluated the antidiabetic and antihyperlipidemic effect of Parquetina nigrescens in streptozotocin-nicotinamide-induced type 2 diabetic rats.

Methods

Type 2 diabetes mellitus was induced in overnight fasted rats with a single intraperitoneal injection of streptozotocin (60 mg/kg), followed by the administration of nicotinamide (120 mg/kg) after an interval of 15 min. Diabetic rats were orally administered with; 200, 400 and 800 mg/kg of aqueous extract of Parquetina nigrescens (AEPN), metformin (180 mg/kg) and glibenclamide (1 mg/kg) for two weeks. The effect of treatments on fasting blood glucose, serum insulin, leptin, adiponectin, homa-ir, lipid profile, body weight, pancreatic antioxidants parameters, hepatic glycogen content, glucose-6-phosphate activity, α-amylase inhibition, α-glucosidase inhibition, lipase inhibition and histology of the organs were evaluated.

Results

Data from this study showed that treatment with AEPN produced a significant reduction (p < 0.05) in fasting blood glucose, glucose-6-phosphatase activity, serum lipase, total triglyceride, total cholesterol, low-density lipoproteins, very low-density lipoprotein, atherogenic index, coronary risk index, pancreatic α-amylase, α-glucosidase and lipase activities. Treatment with AEPN also produced a significant (p < 0.05) increase in; glucose tolerance, glycogen content, leptin, adiponectin and pancreatic antioxidants (glutathione, superoxide dismutase, catalase and high-density lipoproteins). The histology of the organ showed regeneration of the pancreatic tissue after treatment with AEPN.

Conclusions

This study showed that AEPN exhibited antidiabetic and antihyperlipidemic activity in streptozotocin-nicotinamide-induced type 2 diabetic rats.

Detection and molecular characterization of a first isolate of rabbit haemorrhagic disease virus in Nigeria

Rabbit haemorrhagic disease virus (RHDV) was recovered from necropsied rabbits that died during an outbreak characterized by epistaxis, incoordination, paralysis, and multi-organ haemorrhages in Ilorin, Nigeria. The haemagglutination test (HA) and RT-PCR assay targeted against a fragment of the RHDV VP60 gene were performed on liver, spleen, and kidney homogenates; faeces; and urine obtained from the rabbits. Amplicons were purified, sequenced, and phylogenetically analysed. The liver homogenates yielded the highest HA titres while RT-PCR of liver, spleen, and kidneys yielded the expected 1252 bp band. Sequence and phylogenetic analyses revealed that the Nigerian RHDV strain (RHDV/NGR/ILN/001) was 98.57%, 97.95%, and 96.70% homologous with RHDV2 (RHDVGI.2) strains from the Netherlands, Germany, and France, respectively. RHDV/NGR/ILN/001 induced tracheal, intestinal, and mediastinal lymph node haemorrhages, pulmonary oedema and congestion, and enlarged, necrotic liver in experimentally inoculated rabbits. The implications of this study, which is the first report of RHDV in Nigeria, are discussed.

Molecular and pathological investigation of a natural outbreak of Newcastle disease caused by genotype XVII in White Leghorn chickens

ABSTRACT Newcastle disease (ND) is an infectious viral poultry disease with great economic consequences. In developing countries, outbreaks of ND caused by virulent Newcastle disease virus (NDV) have been identified as a limiting factor to the growth of the poultry industry. Limited reports exist on the pathology of natural field infection caused by NDV genotype XVII in chickens. Here, we present clinical, pathological and molecular investigation of confirmed ND in a 24-week-old layer-type, semi-intensive poultry flock with recorded mortality of over 50%. During PM examination, tissues were harvested for virus isolation, histopathology and immunohistochemistry. Virus isolation was performed in 10-day-old embryonated chicken eggs, and a haemagglutinating agent thereof identified by one-step reverse transcription-polymerase chain reaction (RT-PCR). For the genotyping of the isolate, the full fusion gene was sequenced. Clinical signs observed included general body lethargy, inappetence and greenish diarrhoeic faeces from the cloaca before death with daily mortality exceeding 100 chickens. The pathology was characteristic of a viral haemorrhagic infection, with serosal haemorrhages, mucosal surface erosion and ulceration. In most of the carcasses, the main lesions seen included airsacculitis, meningeal congestion, haemorrhagic oophoritis, pancreatic necrosis, enteritis and faecal matting of the vent. Virus isolation and RT-PCR made a confirmatory diagnosis of ND. Based on the cleavage site motif sequence (¹¹²RRQKR/F¹¹⁷), the isolate was identified as a virulent strain with phylogenetic analysis showing clustering in genotype XVII viruses. To the best of the authors' knowledge, this is the first report describing the pathological findings of a natural outbreak caused by NDV involving viruses of genotype XVII. RESEARCH HIGHLIGHTS First report of a natural outbreak of Newcastle disease in White Yarkon Leghorns. The outbreak was caused by virulent NDV belonging to genotype XVII. Pathology differed slightly from those in experimental studies using SPF and other unvaccinated chickens.

Peste Des Petits Ruminants Virus and Goatpox Virus Co-Infection in Goats

Infection of small ruminants with peste des petits ruminants virus (PPRV) and goatpox virus (GTPV) are endemic and can have devastating economic consequences in Asia and Africa. Co-infection with these viruses have recently been reported in goats and sheep in Nigeria. In this study, we evaluated samples from the lips of a red Sokoto goat, and describe co-infection of keratinocytes with PPRV and GTPV using histopathology and transmission electron microscopy. Eosinophilic cytoplasmic inclusion bodies were identified histologically, and ultrastructural analysis revealed numerous large cytoplasmic viral factories containing poxvirus particles and varying sizes of smaller cytoplasmic inclusions composed of PPRV nucleocapsids. These histopathological and ultrastructural findings show concurrent infection with the 2 viruses for the first time as well as the detection of PPRV particles in epithelial cells of the mucocutaneous junction of the lip.

Natural outbreak of Marek's disease in indigenous chicken and Japanese quail (Coturnix coturnix japonica) in Jos, Plateau State, Nigeria

Carcasses of an indigenous adult chicken and Japanese quail from different flocks were presented to a veterinary clinic for postmortem (PM) examination in 2014 in Jos, Plateau State, Nigeria. PM observations revealed cutaneous, hepatic, and splenic tumors in the Indigenous chicken. The quail carcass was emaciated with hepatic tumors. Histopathology revealed severe focally extensive non-encapsulated circumscribed large nodules with pleomorphic population of cells mainly composed of lymphoplasmacytic and mixed neutrophilic polymorphonuclear cells in the chicken. The pleomorphic infiltration of lymphohistioplasmacytic cells mixed with neutrophilic polymorphonuclear cells in the quail was consistent with Marek’s disease virus (MDV) infection. Polymerase chain reaction (PCR) was carried out, and the Meq oncogene of the MDV was amplified in the samples collected from the chicken and quail to confirm the presence of the virulent MDV. The samples were also subjected to PCR for detection of MDV Rispens CVI988 vaccine strain which was detected in both chicken and quail samples. The findings in this study represent the first report of confirmatory diagnosis of MD using histopathology in an indigenous chicken and Japanese quail in Nigeria. It is also the first report of the detection of MDV Rispens CVI988 vaccine strain in unvaccinated chicken and quail in Nigeria.

Co-infection of peste des petits ruminants and goatpox in a mixed flock of sheep and goats in Kanam, North Central Nigeria

Peste‐des‐petits‐ruminants (PPR) and Goat pox (GTP) are two devastating and economically important transboundary animal diseases of small ruminants in Africa and Asia that have been difficult to control. This study however, investigated an outbreak of PPR and GTP in a mixed flock of indigenous sheep and goats in Kanam, North Central Nigeria. A total of nine sera and seven tissues (lungs, spleen, scab and skin) samples were collected and analysed in the laboratory using competitive enzyme linked immunosorbent assay (cELISA) for PPR antibodies and polymerase chain reaction (PCR) for detection of PPR virus (PPRV) and GTP virus (GTPV). Gene fragments of the nucleoprotein of PPRV and the G‐protein‐coupled chemokine receptor (GPCR) of GTPV were amplified and sequenced to confirm the presence of the causative viruses. Serologically, antibodies to PPRV were detected in all (9/9) sera collected. GTPV and PPRV was detected in corresponding samples (42.8% n = 3/7) of the scab/skin samples collected by both PCR and RT‐PCR technique. The phylogenetic analysis of PPRV revealed that the virus belongs to lineage IV and clustered with viruses from Gabon and Cameroon. Similarly, the GTPV also clustered with other sequences from Burkina Faso and Yemen. The positive cELISA, RT‐PCR and PCR results from samples collected from the same animals confirmed co‐infection of PPR and GTP in this mixed flock of sheep and goats. This is the first report of concurrent infection of PPR and GTP in mixed flock of sheep and goats in Nigeria. Our findings underscore the need for farmers to vaccinate their flock to control spread and economic losses as result of these diseases.