Serological Evidence of Antibodies to Rift Valley Fever Virus in Wild and Domestic Animals in Bauchi State, Nigeria.

Rift Valley fever (RVF) is an arthropod-borne zoonotic disease responsible for severe outbreaks in livestock and humans with concomitant economic losses in many countries in sub-Saharan Africa. The study, therefore, investigated the seroprevalence of the Rift Valley fever virus (RVFV) among wild and domestic animals. Blood samples were collected between 2013 and 2015 from 106 wild animals, 300 cattle (Bos indicus), and 200 horses (Equus caballus), respectively, in Yankari Game Reserve (YGR) and Sumu Wildlife Park (SWP) in Bauchi state, Nigeria. Harvested sera from blood were evaluated for the presence of anti-RVFV IgM/IgG antibodies. The overall seroprevalence in cattle was 11.3% (p = 0.677; 95% CI: 0.624-0.730) and in wildlife was 8.5% (p = 0.006; 95% CI: 0.00-0.60). The diversity of wildlife species sampled indicated seropositivity of 36.0% in waterbuck (Kobus ellipsiprymus), 25.0% in elephant (Loxodonta africana), 12.5% in eland (Taurotragus oryx), and 8.3% in wildebeest (Connochaetes taurinus). Whereas, samples from zebra (Equus quagga crawshayi), kudu (Tragelaphus strepsiceros), and hartebeest (Alcelaphus buselaphus caama) did not show detectable antibodies to RVFV, and seroprevalence in female (15.0%) wildlife species was higher than in males (4.5%) (p = 0.061). Classification of cattle into breed and sex showed no significant difference in seropositivity. Seropositivity of 12.0% was observed in White Fulani, 12.1% in Red Bororo, and 7.8% in Sokoto Gudali breeds of cattle (p = 0.677). Whereas, seropositivity of 13.6% was observed in females and 6.4% observed in males (p = 0.068). This study indicated the presence of antibodies to RVFV among some wild animals and cattle in the absence of a reported outbreak in the study area. The circulation of RVFV in the study area may pose a significant health risk to livestock, wildlife, and humans. Therefore, surveillance for RVFV should be intensified targeting mosquito vectors and humans in Bauchi state, Nigeria.

Toxicological evaluation of repeated administration of povidone iodine in cockerels.

Povidone-iodine (Polidine®) is a synthetic broad-spectrum antiseptic being applied topically to treat wounds and prevent their infection. It has been however reported with the assertions that it is effective in the treatment of infectious bursa disease (IBD) when administered orally by practicing Veterinarians and other poultry handlers. Acute kidney injury has been reported also with povidone iodine ingestion. Hence, in this study, graded dose administration was conducted to ascertain its safety profile. Forty chicks were obtained from a poultry hatchery in Ibadan, Oyo State. They were randomly divided into four (4) groups of ten chicks each. Group I served as negative control, groups II, III and IV were administered Polidine® at 1 mL/50 L, 1 mL/25 L, and 1 mL/10 L of water respectively for 7 days. Blood samples were collected on Days 3 and 7 post administration for determination of haematological and biochemical parameters. Liver and Kidney tissues were harvested following termination of the experiment and processed for histopathological examination. Results revealed no significant (p > 0.05) effect in the haematological and biochemical parameters of cockerels treated with Povidone iodine at 1 mL/50 and 25 L of water. On histopathological examination no lesion was also observed in the liver and kidney tissues of groups I, II and III (normal control, 1 mL/50 and 25 L respectively) when compared to group IV (1 mL PI /50 L of water) where lesions were recorded. Hence, this study has shown the relative safety of povidone iodine at different doses in cockerels.

Research Note: Evaluation of acute oral toxicity of povidone-iodine in cockerels using the up-and-down procedure.

Povidone-iodine (Polidine) is a synthetic broad-spectrum antiseptic and being applied topically to treat wounds and prevent their infection. It is however used by poultry farmers, field veterinarians, and other animal health workers with the claim that it is effective for treatment of infectious bursal disease when administered orally. Hence, an acute oral toxicity study was conducted to ascertain its safety profile. Ten cockerel chicks were randomly selected and divided into 2 groups of 5 chicks per group. One group served as the negative control, whereas the other group was administered povidone-iodine at a dose of 2,000 mg/kg of BW orally. The blood sample was collected at the end of the study to determine changes in hematological and biochemical parameters. In addition, vital organs were also harvested and preserved for histopathological examinations. The result showed that the median lethal dose (LD50) of the povidone-iodine is higher than 2,000 mg/kg of BW in cockerels. There were no significant changes in the hematological parameters measured. Biochemical evaluation (renal and liver function test) showed an increase in aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase levels after administration of povidone-iodine. The study indicated that the LD50 of povidone-iodine is higher than 2,000 mg/kg of BW of cockerels, and there were increases in urinary and liver enzymes at this dose.

Seroprevalence of Foot and Mouth Disease Virus Infection in Some Wildlife and Cattle in Bauchi State, Nigeria.

Foot and mouth disease (FMD) is an important transboundary viral disease of both domestic and wild cloven-hoofed animals characterized by high morbidity with devastating consequence on the livestock worldwide. Despite the endemic nature of FMD in Nigeria, little is known about the epidemiology of the disease at the wildlife-livestock interface level. To address this gap, blood samples were collected between 2013 and 2015 from some wildlife and cattle, respectively, within and around the Yankari Game Reserve and Sumu Wildlife Park in Bauchi State, Nigeria. Wild animals were immobilized using a combination of etorphine hydrochloride (M99® Krüger-Med South Africa) at 0.5-2 mg/kg and azaperone (Stresnil®, Janssen Pharmaceuticals (Pty.) Ltd., South Africa) at 0.1 mg/kg using a Dan-Inject® rifle (Dan-Inject APS, Sellerup Skovvej, Denmark) fitted with a 3 ml dart syringe and for reversal, naltrexone (Trexonil® Kruger-Med South Africa) at 1.5 mg IM was used, and cattle were restrained by the owners for blood collection. Harvested sera from blood were screened for presence of antibodies against the foot and mouth disease virus (FMDV) using the PrioCHECK® 3ABC NSP ELISA kit, and positive samples were serotyped using solid-phase competitive ELISA, (IZSLER Brescia, Italy). Out of the 353 sera collected from cattle and wildlife 197 (65.7%) and 13 (24.5%) (P < 0.05), respectively, tested positive for antibodies to the highly conserved nonstructural 3ABC protein of FMDV by the FMDV-NS blocking ELISA. Classification of cattle into breed and sex showed that detectable antibodies to FMDV were higher (P < 0.05) in White Fulani 157 (72.8%) than in Red Bororo 23 (39.7%) and Sokoto Gudali 17 (33.3%) breeds of cattle, whereas in females, detectable FMDV antibodies were higher (P < 0.05) 150 (72.8%) than in males 47 (50.0%). In the wildlife species, antibodies to FMDV were detected in the waterbucks 2 (28.6%), elephant 1 (25.0%), wildebeests 4 (33.3%), and elands 6 (25.0%). Four serotypes of FMDV: O, A, SAT 1, and SAT 2 were detected from the 3ABC positive reactors in waterbucks, elephants, wildebeests, and elands. The results showed presence of antibodies to FMDV in some wildlife and cattle and suggested that wildlife could equally play an important role in the overall epidemiology of FMD in Nigeria. FMD surveillance system, control, and prevention program should be intensified in the study area.

Application of loop-mediated isothermal amplification assay in the detection of herpesvirus of turkey (FC 126 strain) from chicken samples in Nigeria.

AIM: This study was designed to optimize and apply the use of loop-mediated isothermal amplification (LAMP) as an alternative to conventional polymerase chain reaction (PCR) for the detection of herpesvirus of turkeys (HVT) (FC 126 strain) in vaccinated and non-vaccinated poultry in Nigeria. MATERIALS AND METHODS: HVT positive control (vaccine) was used for optimization of LAMP using six primers that target the HVT070 gene sequence of the virus. These primers can differentiate HVT, a Marek's disease virus (MDV) serotype 3 from MDV serotypes 1 and 2. Samples were collected from clinical cases of Marek's disease (MD) in chickens, processed and subjected to LAMP and PCR. RESULTS: LAMP assay for HVT was optimized. HVT was detected in 60% (3/5) and 100% (5/5) of the samples analyzed by PCR and LAMP, respectively. HVT was detected in the feathers, liver, skin, and spleen with average DNA purity of 3.05-4.52 µg DNA/mg (A260/A280) using LAMP. Conventional PCR detected HVT in two vaccinated and one unvaccinated chicken samples, while LAMP detected HVT in two vaccinated and three unvaccinated corresponding chicken samples. However, LAMP was a faster and simpler technique to carry out than PCR. CONCLUSION: LAMP assay for the detection of HVT was optimized. LAMP and PCR detected HVT in clinical samples collected. LAMP assay can be a very good alternative to PCR for detection of HVT and other viruses. This is the first report of the use of LAMP for the detection of viruses of veterinary importance in Nigeria. LAMP should be optimized as a diagnostic and research tool for investigation of poultry diseases such as MD in Nigeria.

Characterization of field and vaccine infectious bursal disease viruses from Nigeria revealing possible virulence and regional markers in the VP2 minor hydrophilic peaks.

Outbreaks of infectious bursal disease in vaccinated chicken flocks are frequent in Nigeria. For the control of infectious bursal disease, live vaccines based on foreign infectious bursal disease virus (IBDV) strains are used. The present study investigated the phylogenetic relationship between field and vaccine IBDV strains from northwestern Nigeria. Thirty field IBDV strains and three commercial vaccines strains were characterized through sequencing the VP2 hypervariable region. In addition, the complete genome segment A coding region for two vaccines and two field strains was sequenced. The deduced amino acid sequences (position 212 to 331) of IBDV strains from Nigeria and other regions of the world were aligned and possible regional and virulence markers were identified associated with VP2 minor hydrophilic peaks. Reversion to virulence of a vaccine strain with a Q to L mutation at position 253 was observed. Phylogenetic analyses revealed a unique cluster of northwest Nigerian field IBDV strains alone or related to imported characterized classical and very virulent IBDV vaccines. The results suggest that when IBDV strains spread from their region of origin to a different region they mutate alongside indigenous field strains but may retain their identity on the VP2 region.

Serologic evidence of infection with H5 subtype influenza virus in apparently healthy local chickens in Kaduna State, Nigeria.

A serologic survey for antibodies against H5 subtype influenza virus in 605 apparently healthy local chickens using a hemagglutination inhibition test was carried out in 12 local government areas of Kaduna state, Nigeria. An overall prevalence of 18.1% was recorded, with a higher prevalence of 27.3% in six local government areas that have not reported outbreaks of highly pathogenic avian influenza (HPAI) H5N1 virus and a lower prevalence of 7.5% in six local government areas that had reported and confirmed outbreaks of HPAI H5N1 virus between 2006 and 2007. There was association between the presence of ducks and detection of H5 antibodies (P = 0.000, odds ratio = 0.22). The implication of this finding is discussed, although a virologic investigation to verify the findings of this study is highly recommended.

Changes in weight gain, faecal oocyst count and packed cell volume of Eimeria tenella-infected broilers treated with a wild mushroom (Ganoderma lucidum) aqueous extract.

An experiment was conducted to study the effect of a wild Ganoderma lucidum aqueous extract in coccidian-infected broilers. At 6 weeks of age the birds were randomly allocated to 6 treatment groups of 20 Ross broilers each in wire cages. Groups A, B and C were infected with Eimeria tenella Houghton strain at the rate of 36 250 sporulated oocysts/ml per bird. The remaining 3 groups D, E and F were uninfected controls. At 7 weeks the birds in group A were treated with G. lucidum aqueous extract and those in B with amprolium in drinking water ad libitum at the rate of 200 mg/ml each for 7 days consecutively. Body weight gain, feed intake, faecal oocyst output and some haematological parameters were monitored. The result showed that all the infected birds in groups A, B and C had clinical signs of weakness and reduced appetite on day 4 post-infection. By the 5th day post-infection their faeces became bloody and watery, and large numbers of E. tenella oocysts were present in the faeces. On day 3 after treatment the oocysts detected were considerably reduced in both treated groups A and B and slightly higher in the untreated group C. The faeces of the uninfected control groups were normal and free of coccidial oocysts. After treatment for 7 days no coccidial oocysts were found in faeces of the birds that had been treated. Infected, untreated birds showed a slight drop in feed intake and weight gain from 7 to 8 weeks of age. The final mean weight gain recorded in the treated groups A and B was comparable to that of the uninfected birds in the 3 control groups, while it was lower in the untreated group C. The feed to gain ratio was higher in C than in the other groups. A slight drop in packed cell volume was observed in groups A, B and C at 7 weeks of age, 1 week after infection. This study showed that treatment with G. lucidum results in a marked reduction in the number of E. tenella oocysts shed in the faeces, leading to improved weight gain and decreased weight loss. The results confirmed the virulence of the Houghton strain of E. tenella and the effectiveness of both amprolium and G. lucidum extract against E. tenella.

In vitro screening of two Nigerian medicinal plants (Vernonia amygdalina and Annona senegalensis) for anthelmintic activity.

Vernonia amygdalina and Annona senegalensis, two plants used by local/smallholder livestock farmers in Nigeria as anthelmintic were screened for in vitro anthelmintic activity using Haemonchus contortus eggs. The extract of V. amygdalina did not show any significant activity at concentrations up to 11.2mg/ml. The extract of A. senegalensis showed significant (P<0.001) reduction in egg hatch at a concentration of 7.1mg/ml. The in vitro fecal culture of eggs with A. senegalensis showed significant (P<0.001) reductions in larval recovery with increasing concentrations from 1 to 10% ((w/w) in fecal culture) when whole ground plant material was used. Although traditional veterinary healers and local livestock farmers claim both plants are effective as anthelmintics, our result indicate that only A. senegalensis showed promising anthelmintic activity especially with use of ground whole plant materials as used by some farmers.

Snakebites in poultry.

Eight cases of snakebite involving 5 flocks were seen in chickens, ducks and turkeys in the Avian Ambulatory Clinic of the Veterinary Teaching Hospital, Zaria, between July 1983 and August 1990. Most of the clients resided in areas with large canopies of trees and bushes. There was a large gully just behind the residential areas. Twenty-one birds were bitten; chickens constituted 85.7%, turkeys 12% and ducks 4.8% of this number. Hens incubating eggs were most vulnerable. Cocks were usually bitten when they attacked the snakes. Clinical signs were similar to those reported in other animal species. Gross lesions included congestion of visceral organs and hemorrhage in the viscera, around the bite sites and in the sc tissues. There was also im edema around bite sites. The fatality rate was 87.5%.

Campylobacter fetus subsp. jejuni in poultry reared under different management systems in Nigeria.

Cloacal swabs from 487 live birds in 36 flocks and 70 poultry carcasses were cultured for Campylobacter fetus subsp. jejuni. It was isolated from 12.3% of the birds in 19 flocks. Chickens, turkeys, and guinea fowl differed from one another in isolation rates of the organism. Management system affected its occurrence, and only 7.1% of eviscerated carcasses yielded it. It was concluded that bird species, management system, and immersing slaughtered poultry in boiling water before dressing affect recovery of C. fetus subsp. jejuni from live birds and carcasses.

Challenge study on infectious bursal disease in chicks derived from vaccinated hens.

Presence and levels of maternal antibody (MA) in broiler chicks derived from hens vaccinated with a live infectious bursal disease (IBD) vaccine were investigated by a quantitative agar-gel precipitin test. At day old 100% of the chicks tested had MA; by 17 days of age it was present in only 10%. The mean MA level at day old was 337.5 UK units/ml but decreased to 6.3 UK units/ml at 17 days of age. Randomly selected chicks from the pool studied were challenged at weekly intervals from day old for 29 days with an IBD virus obtained from a natural outbreak. Subclinical and clinical disease were observed in chicks challenged at eight and 29 days of age respectively.

Infectious bursal disease and spirochetosis in pullet chicks.

Infectious bursal disease and spirochetosis were diagnosed simultaneously in a flock of 100 six-week-old babcock pullet chicks. Larvae of the fowl tick Argas persicus were found on the bodies of the chicks. Thirty-nine of the chicks died 5 days after the onset of clinical signs.