Faruku Bande

Progress and challenges toward the development of vaccines against avian infectious bronchitis.

Avian infectious bronchitis (IB) is a widely distributed poultry disease that has huge economic impact on poultry industry. The continuous emergence of new IBV genotypes and lack of cross protection among different IBV genotypes have been an important challenge. Although live attenuated IB vaccines remarkably induce potent immune response, the potential risk of reversion to virulence, neutralization by the maternal antibodies, and recombination and mutation events are important concern on their usage. On the other hand, inactivated vaccines induce a weaker immune response and may require multiple dosing and/or the use of adjuvants that probably have potential safety risks and increased economic burdens. Consequently, alternative IB vaccines are widely sought. Recent advances in recombinant DNA technology have resulted in experimental IB vaccines that show promise in antibody and T-cells responses, comparable to live attenuated vaccines. Recombinant DNA vaccines have also been enhanced to target multiple serotypes and their efficacy has been improved using delivery vectors, nanoadjuvants, and in ovo vaccination approaches. Although most recombinant IB DNA vaccines are yet to be licensed, it is expected that these types of vaccines may hold sway as future vaccines for inducing a cross protection against multiple IBV serotypes.

Prevalence and risk factors of feline leukaemia virus and feline immunodeficiency virus in peninsular Malaysia

BackgroundFeline leukaemia virus (FeLV) and feline immunodeficiency virus (FIV) are major causes of morbidity and mortality in domestic and wild felids. Despite the clinical importance of feline retroviruses and the growing interest in cats as pets, information about FeLV and FIV in Malaysia is presently insufficient to properly advise veterinarians and pet owners. A cross-sectional study was carried out from January 2010 to December 2010 to determine the prevalence and risk factors associated with FeLV and FIV among domestic cats in peninsular Malaysia. Plasma samples were harvested from the blood of 368 domestic cats and screened for evidence of FeLV p27 antigen and FIV antibodies, using an immunochromatographic kit. Additionally, data on cat demographics and health were collected using a structured questionnaire, and were evaluated as potential risk factors for FeLV or FIV status.ResultsOf the 368 cats that were evaluated in this study, 12.2% (45/368; 95% CI = 8.88 - 15.58) were positive for FeLV p27 antigen, 31.3%, (115/368; 95% CI = 26.51 - 35.99) were seropositive to FIV antibodies, and 4.3% (16/368; 95% CI = 2.27 - 6.43) had evidence of both viruses. Factors found to significantly increase the risk for FeLV seropositivity include sex, age, behaviour, sickness, and living in a multi-cat household. Seropositive response to FIV was significantly associated with sex, neuter status, age, behaviour, and health status.ConclusionsThe present study indicates that FeLV and FIV are common among domestic cats in peninsular Malaysia, and that factors related to cat demographics and health such as age, sex, behaviour, health status and type of household are important predictors for seropositive status to FeLV or FIV in peninsular Malaysia. High prevalence of FeLV or FIV observed in our study is of concern, in view of the immunosuppressive potentials of the two pathogens. Specific measures for control and prevention such as screening and routine vaccination are needed to ensure that FeLV and FIV are controlled in the cat population of peninsular Malaysia.

Pathogenesis and Diagnostic Approaches of Avian Infectious Bronchitis

Infectious bronchitis (IB) is one of the major economically important poultry diseases distributed worldwide. It is caused by infectious bronchitis virus (IBV) and affects both galliform and nongalliform birds. Its economic impact includes decreased egg production and poor egg quality in layers, stunted growth, poor carcass weight, and mortality in broiler chickens. Although primarily affecting the respiratory tract, IBV demonstrates a wide range of tissues tropism, including the renal and reproductive systems. Thus, disease outcome may be influenced by the organ or tissue involved as well as pathotypes or strain of the infecting virus. Knowledge on the epidemiology of the prevalent IBV strains in a particular region is therefore important to guide control and preventions. Meanwhile previous diagnostic methods such as serology and virus isolations are less sensitive and time consuming, respectively; current methods, such as reverse transcription polymerase chain reaction (RT-PCR), Restriction Fragment Length Polymorphism (RFLP), and sequencing, offer highly sensitive, rapid, and accurate diagnostic results, thus enabling the genotyping of new viral strains within the shortest possible time. This review discusses aspects on pathogenesis and diagnostic methods for IBV infection.

Synthesis and characterization of chitosan-saponin nanoparticle for application in plasmid DNA delivery

Nonviral delivery system receives attention over the last decade. Chitosan (CS) is a cationic polymer whereas saponin (SP) is classified as glycoside. In this study, a spherically-shaped CS-SP nanoparticle was synthesized and characterized. The ability of the nanoparticle to protect DNA from enzymatic degradation, its thermostability and cytotoxicity were evaluated. The particle size was found below 100 nmas determined by Zetasizer, transmission electron microscopy (TEM), and field scanning electron microscopy (FSEM) results. The surface charge ranges from 43.7 mV to 38.5 mV before and after encapsulation with DNA plasmid, respectively. In terms of thermostability, Thermal Gravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC) revealed that CS-SP nanoparticle had a melting temperature of 110 °C, with rapid decomposition occurring at 120 °C. Encapsulation of DNA with the synthesized nanoparticle was evidenced by changes in the FTIR spectra including characteristic peaks at 3267.39 and 1635.58 cm-1, wave numbers. Additional peak was also observed at 1169.7 cm-1 following encapsulation. Electrophoretic mobility showed that CS-SP nanoparticle protected plasmid DNA from enzymatic degradation, while cell viability assays confirmed that the synthesized nanoparticle exhibited low cytotoxicity at different concentrations in avian cells. Taken together these, CS-SP nanoparticle showed potentials for applications as a DNA delivery system.

Molecular Characterization of Human Rotavirus from Children with Diarrhoeal Disease in Sokoto State, Nigeria

This study was conducted to detect and characterize prevalent human group A rotavirus strains from 200 diarrheic children in Sokoto, Nigeria, by ELISA, monoclonal antibody (Mab) serotyping and Reverse Transcription-Polymerase Chain Reaction (RT-PCR) techniques. Rotavirus was detected in 25.5% of the children. The G-serotypes observed in circulation were G4: 16 (59.3%), G1: 4 (14.8%), G2: 3 (11.1%), G3: 3 (11.1%), and G12: 1 (3.7%). The monoclonal antibody (Mab) serotyping detected G1 and G3 but did not detect G4 and G2 serotypes. The Mab typing of the G1 and G3 serotypes was consistent with the result of the RT-PCR. The VP4 genotypes detected were P[6] 3 (13%), P[8] 11 (47.8%), and the rare human P genotype (P[9]), found in 9 patients (39.1%). Nine strains identified with the common G and P combinations were G4 P[8] 5 (56%), G4 P[6] 1 (11%), G1 P[8] 2 (22%), and G3 P[8] 1 (11%), while seven strains with unusual combinations or rare G or P genotypes identified were G12 P[8] 1 (14%), G2 P[8] 2 (29%), and G4 P[9] 4 (57%). To our knowledge this is the first molecular study of human rotavirus and report of rare human G and P serotypes in Sokoto State.

Prediction and In Silico Identification of Novel B-Cells and T-Cells Epitopes in the S1-Spike Glycoprotein of M41 and CR88 (793/B) Infectious Bronchitis Virus Serotypes for Application in Peptide Vaccines

Bioinformatic analysis was used to predict antigenic B-cell and T-cell epitopes within the S1 glycoprotein of M41 and CR88 IBV strains. A conserved linear B-cell epitope peptide, YTSNETTDVTS175–185, was identified in M41 IBV strains while three such epitopes types namely, VSNASPNSGGVD279–290, HPKCNFRPENI328–338, and NETNNAGSVSDCTAGT54–69, were predicted in CR88 IBV strains. Analysis of MHCI binding peptides in M41 IBV strains revealed the presence of 15 antigenic peptides out of which 12 were highly conserved in 96–100% of the total M41 strains analysed. Interestingly three of these peptides, GGPITYKVM208, WFNSLSVSI356, and YLADAGLAI472, relatively had high antigenicity index (>1.0). On the other hand, 11 MHCI binding epitope peptides were identified in CR88 IBV strains. Of these, five peptides were found to be highly conserved with a range between 90% and 97%. However, WFNSLSVSL358, SYNISAASV88, and YNISAASVA89 peptides comparably showed high antigenicity scores (>1.0). Combination of antigenic B-cells and T-cells peptides that are conserved across many strains as approach to evoke humoral and CTL immune response will potentially lead to a broad-based vaccine that could reduce the challenges in using live attenuated vaccine technology in the control of IBV infection in poultry.

Ultrastructure of Felis catus whole fetus (Fcwf-4) cell culture following infection with feline coronavirus

Abstract Feline coronavirus (FCoV) consists of two biotypes based on their growth in cell culture and their antigenicity. Infections with FCoV are highly prevalent in the cat population worldwide. In this study, Felis catus whole fetus (Fcwf-4)cell culture was infected with FCoV UPM11C/08. Virus multiplication in cell culture was monitored and examined under the transmission electron microscope. The virus particles revealed the characteristic morphology of feline FCoV represented by envelope viruses surrounded by peplomers. Virus attachment and entry into the cell occurred 15 h post-infection (pi), and the myriad of virus particles were observed both extracellularly and intracellularly after 48 h pi. Thereafter, intracellular virus particles were observed to be present in vacuoles or present freely in the cytoplasm.

Major epidemiological factors associated with leptospirosis in Malaysia

INTRODUCTION Leptospirosis is a zoonotic disease caused by a diverse pathogenic leptospira species and serovars. The disease is transmitted directly following contact with infected urine and other body fluids or indirectly after contact with water or soil contaminated with infected urine. OBJECTIVES While a wide range of domestic and wild animals are known to be reservoirs of the disease, occupation, international travel and recreation are beginning to assume a center stage in the transmission of the disease. The objective of this study is to review available literatures to determine the extent to which these aforementioned risk factors aid the transmission, increase incidence and outbreak of leptospirosis in Malaysia. STUDY DESIGN The review was conducted based on prevalence, incidence, and outbreak cases of leptospirosis among human and susceptible animals predisposed to several of the risk factors identified in Malaysia. METHODS Literature searchers and reviews were conducted based on articles published in citation index journals, Malaysian ministry of health reports, periodicals as well as reliable newspapers articles and online media platforms. In each case, the newspapers and online media reports were supported by press briefings by officials of the ministry of health and other agencies responsible. RESULTS The disease is endemic in Malaysia, and this was attributed to the large number of reservoir animals, suitable humid and moist environment for proliferation as well as abundant forest resources. Over 30 different serovars have been detected in Malaysia in different domestic and wild animal species. This, in addition to the frequency of flooding which has increased in recent years, and has helped increase the risk of human exposure. Occupation, recreation, flooding and rodent population were all identified as an important source and cause of the disease within the study population. CONCLUSION There is an urgent need for the government and other stakeholders to intensify efforts to control the spread of the disease, especially as it greatly affect human health and the tourism industry which is an important component of the Malaysian economy. The risk of infection can be minimized by creating awareness on the source and mode of transmission of the disease, including the use of protective clothing and avoiding swimming in contaminated waters. Moreover, improved diagnostics can also help reduce the suffering and mortalities that follow infection after exposure to infection source.

Prevalence and risk factors of Japanese encephalitis virus (JEV) in livestock and companion animal in high-risk areas in Malaysia

Japanese encephalitis (JE) is vector-borne zoonotic disease which causes encephalitis in humans and horses. Clinical signs for Japanese encephalitis virus (JEV) infection are not clearly evident in the majority of affected animals. In Malaysia, information on the prevalence of JEV infection has not been established. Thus, a cross-sectional study was conducted during two periods, December 2015 to January 2016 and March to August in 2016, to determine the prevalence and risk factors in JEV infections among animals and birds in Peninsular Malaysia. Serum samples were harvested from the 416 samples which were collected from the dogs, cats, water birds, village chicken, jungle fowls, long-tailed macaques, domestic pigs, and cattle in the states of Selangor, Perak, Perlis, Kelantan, and Pahang. The serum samples were screened for JEV antibodies by commercial IgG ELISA kits. A questionnaire was also distributed to obtain information on the animals, birds, and the environmental factors of sampling areas. The results showed that dogs had the highest seropositive rate of 80% (95% CI: ± 11.69) followed by pigs at 44.4% (95% CI: ± 1.715), cattle at 32.2% (95% CI: ± 1.058), birds at 28.9% (95% CI: ± 5.757), cats at 15.6% (95% CI: ± 7.38), and monkeys at 14.3% (95% CI: ± 1.882). The study also showed that JEV seropositivity was high in young animals and in areas where mosquito vectors and migrating birds were prevalent.

Molecular detection, phylogenetic analysis, and identification of transcription motifs in feline leukemia virus from naturally infected cats in malaysia.

A nested PCR assay was used to determine the viral RNA and proviral DNA status of naturally infected cats. Selected samples that were FeLV-positive by PCR were subjected to sequencing, phylogenetic analysis, and motifs search. Of the 39 samples that were positive for FeLV p27 antigen, 87.2% (34/39) were confirmed positive with nested PCR. FeLV proviral DNA was detected in 38 (97.3%) of p27-antigen negative samples. Malaysian FeLV isolates are found to be highly similar with a homology of 91% to 100%. Phylogenetic analysis revealed that Malaysian FeLV isolates divided into two clusters, with a majority (86.2%) sharing similarity with FeLV-K01803 and fewer isolates (13.8%) with FeLV-GM1 strain. Different enhancer motifs including NF-GMa, Krox-20/WT1I-del2, BAF1, AP-2, TBP, TFIIF-beta, TRF, and TFIID are found to occur either in single, duplicate, triplicate, or sets of 5 in different positions within the U3-LTR-gag region. The present result confirms the occurrence of FeLV viral RNA and provirus DNA in naturally infected cats. Malaysian FeLV isolates are highly similar, and a majority of them are closely related to a UK isolate. This study provides the first molecular based information on FeLV in Malaysia. Additionally, different enhancer motifs likely associated with FeLV related pathogenesis have been identified.