Daniel Oladimeji Oluwayelu

Analysis and evaluation of mortality losses of the 2001 African swine fever outbreak, Ibadan, Nigeria

The mortality losses of pigs of various age groups affected by the 2001 African swine fever outbreak in Ibadan Nigeria were analyzed and evaluated. Thirty one thousand nine hundred and sixteen (31,916) pigs on three hundred and six (306) farms reported by the Pig Farmers Association of Nigeria and the State Ministry of Agriculture and Natural Resources were involved. Gross mortality was ninety one percent (91%), while age group mortality ranged from 75.9% (growers), 83.1% (weaners), 91.2% (finishers) and 99.8% (piglets); to 100.0% in gilts, sow and boars. Losses were estimated to worth nine hundred and forty one thousand, four hundred and ninety one dollars, sixty seven cents (US

Isolation and Preliminary Characterization of Chicken Anemia Virus from Chickens in Nigeria

941,491.67). Highest financial loss was from sows (29.5% of total loss), followed by gilts (16.6%), finishers (15.2%), weaners (10.7%), boars (10.6%), growers (10.6%) and piglets (8.2%). Average mortality loss per farm of

Serological Investigation of Akabane Virus Infection in Cattle and Sheep in Nigeria

3076.77 was of great financial and socioeconomic consequences for a developing country like Nigeria with a low Gross Domestic Product figures. In conclusion, the need to immediately revisit and take recommended actions on the 1998 Report of the FAO Consultancy Mission to Nigeria on Control and Eradication of an Outbreak of African swine fever in Western Nigeria is stressed.

High Seroprevelance of West Nile Virus Antibodies Observed in Horses from Southwestern Nigeria

Abstract Chicken anemia virus (CAV) was isolated for the first time from the Nigerian chicken population. The virus was recovered from necropsied birds from broiler and pullet flocks that suffered disease outbreaks tentatively diagnosed as infectious bursal disease. A sensitive polymerase chain reaction (PCR) assay detected CAV DNA in tissues of necropsied birds. Restriction endonuclease analysis performed with the 733-bp PCR product and the Cfo I enzyme indicated at least two different CAVs were circulating among the Nigerian chicken population. Four isolates were obtained from pooled liver and thymus tissues using the MDCC–MSB1 cell line. These isolates were found to be antigenically closely related to the Cuxhaven-1 (Cux-1) reference strain of CAV when reacted with four monoclonal antibodies prepared against the Cux-1 virus. One of the isolates (isolate A) induced thymus atrophy, bone marrow aplasia, and low hematocrit values when inoculated into 1-day-old specific-pathogen-free chickens. These findings not only demonstrate that CAV is present in Nigeria, but they also likely represent the first cell culture isolation of the virus in Africa.

A survey of rabies virus antibodies in confined, hunting and roaming dogs in Ogun and Oyo States, Southwestern Nigeria

Akabane virus (AKAV) is recognized as an important pathogen that causes abortions and congenital malformations in ruminants. However, it has not received adequate attention in Nigeria. Therefore, in investigating this disease, serum samples from 184 (abattoir and farm) head of cattle and 184 intensively reared sheep from two states in southwest Nigeria were screened for antibodies against AKAV using enzyme-linked immunosorbent assay. An overall seropositivity of 70.1% (129/184) was obtained with antibodies being detectable in 73.8% of abattoir (trade) cattle and 40.0% in farm cattle, while 4.3% (8/184) seropositivity was observed in sheep. All the age groups of cattle tested had seropositive animals, 0-1 year (1/7, 14.3%), 2-3 years (17/34, 50.0%), 4-5 years (92/121, 76.0%), and >5 years (19/22, 86.4%), while in sheep only the age groups of 2-3 and 4-5 years showed seropositivity of 4.1% (4/97) and 8.2% (4/49), respectively. The detection of antibody-positive animals among unvaccinated cattle and sheep provides evidence of AKAV infection in Nigeria. These findings call for continuous monitoring of the disease among ruminants in order to ascertain the actual burden and increase awareness of the disease. This will facilitate early detection and aid the development of appropriate control measures against the disease in Nigeria.

Occurrence of Newcastle Disease and Infectious Bursal Disease Virus Antibodies in Double-Spurred Francolins in Nigeria.

To investigate exposure of Nigerian horses to West Nile virus (WNV), we determined the seroprevalence rate of anti-WNV antibody in a cohort of 145 horses. Serum samples were collected from three locations in southwestern Nigeria between October, 2011, and July, 2012. The horses were asymptomatic and unvaccinated against WNV at the time of sampling. All sera were tested using a competition enzyme-linked immmunosorbent assay (ELISA) and by an immunoglobulin M (IgM)-specific ELISA. High rates of anti-WNV antibody prevalence were observed in all locations with a mean level of 90.3% (95% confidence interval 84.3-94.6%). None of the horses had detectable anti-WNV IgM. This is the first ELISA-based report of WNV seroprevalence in Nigerian horses and suggests that WNV is enzootic in the study areas, indicating a potential risk of infection in humans and animals.

Chikungunya Virus Seroprevalence and Associated Factors among Hospital Attendees in Two States of Southwest Nigeria: A Preliminary Assessment

Abstract Objective To screen for rabies virus (RABV) antibodies in apparently healthy confined, hunting and roaming dogs by a community-based approach. Methods Sera from 230 (80 confined, 92 hunting and 58 roaming) dogs in some urban and peri-urban communities in Ogun and Oyo states, Southwestern Nigeria were screened for RABV antibodies using the indirect ELISA method. Results Analysis of administered questionnaires showed that of 80 confined dog owners, 37 were aware of anti-rabies vaccination ( i.e. they were informed) while 17 were negligent and 26 uninformed. Of the 230 sera tested, only 13 (5.7%) from vaccinated confined dogs in Oyo state were positive ( i.e. had optimal RABV antibody titres) (mean 0.54, 95% CI : 0.42–0.67) while all confined dog sera in Ogun state were negative. Eleven (12.0%) and 14 (24.1%) of the hunting and roaming dogs respectively had sub-optimal RABV antibody titres while the rest were negative. Conclusions Evidently, these groups of dogs are a totally unprotected and susceptible dog population that can serve as potential reservoirs of RABV in the study area. Responsible pet ownership, vaccination of hunting and roaming dogs, and community-based active rabies surveillance are therefore advocated in Nigeria.

Detection of avian nephritis virus and chicken astrovirus in Nigerian indigenous chickens

The double-spurred francolin Francolinus bicalcaratus has been identified as a good candidate for future domestication due to the universal acceptability of its meat and its adaptability to anthropogenically altered environments. Therefore, in investigating the diseases to which they are susceptible, serum samples from 56 francolins in a major live-bird market (LBM) in Ibadan, southwestern Nigeria, were screened for antibodies against Newcastle disease (ND) and infectious bursal disease (IBD) viruses. Haemagglutination inhibition (HI) test and enzyme-linked immunosorbent assay (ELISA) revealed 25.0% and 35.7% prevalence of ND virus (NDV) antibodies, respectively, while 5.4% and 57.1% prevalence of IBD virus (IBDV) antibodies was detected by agar gel precipitation test (AGPT) and ELISA, respectively. This first report on the occurrence of NDV and IBDV antibodies in apparently healthy, unvaccinated double-spurred francolins from a LBM suggests that they were subclinically infected with either field or vaccine viruses and could thus serve as possible reservoirs of these viruses to domestic poultry. Furthermore, if they are to be domesticated for intensive rearing, a vaccination plan including ND and IBD should be developed and implemented.

Epidemiology and ecology of West Nile virus in sub-Saharan Africa

ABSTRACT Chikungunya virus (CHIKV) is a re-emerging pathogen causing long-term polyarthritis and encephalitis. In conducting a preliminary investigation, we hypothesized that there is no serologic evidence of CHIKV infection among attendees of selected hospitals in Lagos and Osun States, Nigeria. Sera from 304 consecutively selected participants were screened for CHIKV IgG and IgM using ELISA. Findings were analyzed vis-à-vis participants’ demographic and clinical data. Over 90.0% of the participants had never heard of CHIKV despite the fact that a large proportion of them (88.8%) had secondary/tertiary education. Overall, 41.8% were positive for, at least, one antibody type (IgG or IgM), while about 16.0% of the participants had dual seropositivity (CHIKV IgG and IgM) with gender as associated factor (odds ratio [OR]: 2.8, p = 0.03). Prevalence rates were 31.8% and 38.4% for CHIKV IgG and IgM, respectively. Only hospital location (Osogbo) was associated with CHIKV IgG (OR: 2.2, p = 0.009), while gender alone was associated with CHIKV IgM (OR: 3.0, p = 0.001). Participants seropositive for CHIKV antibodies were mostly adults (18–59 yrs) belonging to the active work-force; five (22.7%) and three (20.0%) of the pregnant participants had CHIKV IgG and IgM, respectively. Detection of CHIKV IgM in some participants might make them potentially infectious to the newborn and mosquito vectors. Importantly, participants positive for either IgG or IgM had fever (72.8%, 67.2%) and general body pains (61.7%, 57.6%), respectively. This ELISA-based study revealed serologic evidence of CHIKV infection among hospital attendees in Lagos and Osun states with the group-specific prevalence rates being considerably high. Abbreviations:Chikungunya virus (CHIKV); Chikungunya (CHIK); enzyme-linked immunosorbent assay (ELISA); immunoglobulin G or M (IgG/IgM); odds ratio (OR); non-structural proteins (nsP); hemagglutination inhibiting (HI); complement fixing (CF); neutralization test (NT); immunofluorescence assay (IFA); plaque reduction neutralization test (PRNT); confidence interval (CI); analysis of variance (ANOVA); body temperature (BT); Building Nigeria’s Response to Climate Change (BNRCC).

Endemic and emerging arboviral diseases of livestock in Nigeria: a review

Avian nephritis virus (ANV) and chicken astrovirus (CAstV) are widely distributed in poultry flocks worldwide, causing growth retardation. However, these avian astroviruses have not been previously diagnosed in poultry species in Nigeria. Real-time reverse transcriptase-polymerase chain reaction (rRTPCR) and reverse transcriptase-polymerase chain reaction (RT-PCR) were used for detecting ANV and CAstV in gut contents of apparently healthy Nigerian indigenous chickens. The rRT-PCR assay detected ANV and CAstV in 12 of 13 (92.3%) and 7 of 13 (53.9%) gut content pools, respectively. Using two different primer pairs which amplified approximately 2500 base pairs (bp) and 560 bp fragments in the capsid and polymerase genes of ANV and CAstV, respectively, the RT-PCR assay detected specific ANV and CAstV gene sequences in 4 of 5 (80%) and 2 of 3 (66.7%) rRT-PCR-positive samples in that order. The detection of ANV and CAstV in 8 to 20 week-old Nigerian indigenous chickens indicates that these viruses are probably endemic in the flocks or the environment. This study not only represents the first detection of ANV and CAstV in Nigerian poultry, it is the first report establishing the presence of these two viruses in indigenous chickens.