Serological and molecular evidence of bluetongue in sheep and goats in Uttar Pradesh, India

Cross-sectional experimental study was conducted with the objective to estimate the seroprevalence on the basis of antibodies to VP7 protein of bluetongue virus by competitive enzyme linked immunosorbent assay (c-ELISA), to test the neutralizing ability of the antibody to reference strains of 4 BTV serotypes (BTV-1, 2, 10 and 23) by micro serum neutralization assay (m-SNT), to check the presence of BTV dsRNA and to isolate and characterize bluetongue virus (BTV). A total of 91 serum and 26 whole blood samples were obtained from sheep and goat. The study was conducted between September and November, 2012 when the culicoides midges’ activity is maximal. The animals were observed for clinical signs of BTV infection and serum samples were obtained from all animals for c-ELISA and m-SNT. Further, blood samples were collected from the c-ELISA positive animals and subjected to virus isolation and nested RT-PCR. Out of 91 animals tested, 26 (28.6%) were found to be seropositive by c-ELISA and one sheep showed neutralizing antibody against BTV-1 serotype at a titer of 1.2 log10. Multivalent logistic regression analysis of risk factors like age, sex, body condition and species of animals were considered during the serological study and found that species of animal had significant influence (χ2 = 17.111, P<0.05) in seropositivity of BTV. Goats showed more seropositivity to bluetongue as compared to sheep (OR = 0.233). Other risk factors had no significant influence (P>0.05) on seropositivity. It was worth enough to conclude that higher seroprevalence among goats indicated that goats would be the most important animals in the epidemiology of BTV with less clinical manifestation due to development of acquired immunity as the result of continuous exposure.Keywords: Bluetongue virus (BTV), competitive enzyme linked immunosorbent assay (c-ELISA), goat, seroprevalence, sheep, micro serum neutralization assay (m-SNT), nested reverse transcription polymerase chain reaction (RT-PCR)African Journal of Biotechnology Vol. 12(19), pp. 2699-270

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Molecular and phenotypic characterization of shigatoxigenic Escherichia coli (STEC) and enteropathogenic E. coli (EPEC) from piglets and infants associated with diarrhoea in Mizoram, India

Limited information is available on shiga toxin producing Escherichia coli (STEC) in pigs and infants from Aizawl, Mizoram and North Eastern region of India. This cross sectional study was conducted on faecal samples from pigs and infants to detect and characterize of STEC and enteropathogenic E. coli (EPEC). Serogrouping, molecular and phenotypic characterizations were done by standard molecular and cytotoxic assays. Out of 48 E. coli strains isolated from 320 diarrhoeic fecal samples of piglets, 44 belonged to 18 different serogroups, 3 (6.25%) were untypeable (UT) and 1(2.08%) was recorded as rough strain (R). Similarly, out of 17 E. coli strains isolated from 264 diarrhoeic fecal samples of infants, 16 belonged to O60 (94.1%) and 1(5.88%) was untypeable. Virulence genes (stx1, stx2, eaeA and hlyA) were detected by multiplex PCR assay. A total of 1260 E. coli were isolated from piglets (720) and infants (540) from 584 faecal samples. All together, 5.16% (65) E. coli isolates were found to be positive for at least one virulence gene (6.66% piglets and 3.15% infants). Out of the virulent gene positive E. coli 3.17% (32 from piglets and eight from infants) and 1.98% (16 from piglets and nine from infants) were recorded as STEC and EPEC, respectively. On the other hand, from the total 2.14% stx2 positive isolates, 16 and 11 were positive for stx2e and stx2c subtypes, respectively. Similarly, from the 4.04% eaeA positive isolates, 1.19% (15) were positive for bfpA gene, of which 1.67% (12) were piglets and 0.60% (3) were infants. All the isolates were exhibited varying degree of CPE on vero cell lines. In conclusion, STEC and EPEC seem to be associated with diarrhoea in piglets and infants in Mizoram. In piglets STEC strains represent as a major cause of diarrhoea while EPEC strains represent as major cause of diarrhoea in infants in North Eastern region of the India.Keywords: Enteropathogenic E. coli (EPEC), infants; piglets, shigatoxigenic E. coli (STEC), vero cell cytotoxicityAfrican Journal of Biotechnology, Vol 13(12), 1452-146

Bluetongue disease in small ruminants in south western Ethiopia: cross-sectional sero-epidemiological study

Abstract Objective The status of bluetongue disease, vectors for transmission of the disease and the serotypes involved are not clearly known in Ethiopia. This sero-epidemiological study was conducted to determine the seroprevalence and associated risk factors of bluetongue in small ruminants of South Western Ethiopia. Result 422 serum samples were screened for the presence of bluetongue virus (BTV) specific antibodies using competitive enzyme-linked immunosorbent assay (c-ELISA) and 30.6% (129/422) (confidence interval CI 26.2–35%) of the sheep and goat serum samples were found positive. Multivariate analysis of several risk factors like age, sex, altitude, body condition and species of animals were studied and it was observed that species of animals, age and altitude had significant influence (P  0.05) effect on seropositivity to bluetongue

Contagious Bovine Pleuropneumonia: Seroprevalence and Risk Factors in Gimbo District, Southwest Ethiopia

Contagious bovine pleuropneumonia (CBPP) is a highly contagious disease of cattle which is one of the great plagues which continues to devastate the cattle herds on which so many people are dependent in Africa. Cross-sectional study was conducted from October 2015 to August 2016 to determine the seroprevalence of CBPP in cattle and associated risk factors in Gimbo district, Southwest Ethiopia. A total of 384 serum samples were collected and tested for the presence of specific antibodies against Mycoplasma mycoides subspecies mycoides small colony (MmmSC), using a competitive enzyme-linked immunosorbent assay (cELISA). Univariable and multivariable logistic regression analysis were performed to determine the association between risk factors and seroprevalence of CBPP. An overall seroprevalence of CBPP was 8.1% (31/384) and it was ranging from 0% to 20% across different Peasant associations (PAs). The seroprevalence of CBPP among adult animals was 8.5% (25) and in young 6.6% (6), in good body condition animals 6.6% (18) and in poor 11.5% (13), in dry season 11.9% (20) and in rainy 5.1% (11), and in highland altitude 2.5% (3), midland 3.8% (5), and lowland 17.4% (23). Among the potential predisposing factors assessed, altitude was found significantly (p = 0.02, OR = 7.3) associated with the seroprevalence of contagious bovine pleuropneumonia and other risk factors had no significant (P > 0.05) influence. The present study showed that the overall seroprevalence of CBPP in Gimbo district was high and this indicates a need for intervening and implementing control measures to prevent further spread of the disease in the district through the use of better and coordinated vaccination program

Diagnostic performance of a colorimetric RT -LAMP for the identification of SARS-CoV-2: A multicenter prospective clinical evaluation in sub-Saharan Africa

Management and control of the COVID-19 pandemic caused by the severe acute respiratory syndrome coronavirus SARS-CoV-2 is critically dependent on quick and reliable identification of the virus in clinical specimens. Detection of viral RNA by a colorimetric reverse transcription loop-mediated isothermal amplification (RT-LAMP) is a simple, reliable and cost-effective assay, deployable in resource-limited settings (RLS). Our objective was to evaluate the intrinsic and extrinsic performances of RT-LAMP in RLS