Evaluation of diagnostic performance of H-based blocking ELISA for specific detection of peste des petits ruminants in domestic sheep, goats, cattle and camels.

INTRODUCTION: Peste des petits ruminants virus (PPRV) causes a highly devastating disease of sheep and goats, peste des petits ruminants (PPR), which is targeted for global control and eradication by 2030. The serological diagnostic tool kits for accurate diagnosis of PPR have inherent strengths and weaknesses that require parallel validation and optimization across animal species. Thus, the objective of this study was to evaluate diagnostic performance of haemagglutinin based PPR blocking ELISA (HPPR- b-ELISA), that was developed by Africa Union Pan African Veterinary Vaccine Center for specific detection of anti- PPRV antibodies. METHODS: In preliminarily investigation, diagnostic performance of the HPPR-b-ELISA®, commercial PPR competition ELISA (c-ELISA) and virus neutralization test (VNT) were compared for the detection of anti-PPRV antibodies in goats, sheep, cattle and camels. RESULTS: The sensitivity and specificity of HPPR- b-ELISA® were 79.55 and 99.74%, respectively, compared to c-ELISA. The HPPR- b-ELISA® was in perfect agreement (κ = 0.86) with the c-ELISA in all sera collected from goats, sheep and cattle. There was almost perfect agreement between the species of goats (κ = 0.82) and sheep (κ = 0.98), while the agreement was substantial in cattle (κ = 0.78) and no agreement was observed in camels (κ = 0.00). Similarly, the sensitivity and specificity of the HPPR b-ELISA were 80 and 96.36%, respectively compared to VNT with almost perfect agreement in goats (κ = 0.83) and sheep (κ = 0.89), moderate in cattle (κ = 0.50) and none in camels (κ = 0.00). CONCLUSION: Our study revealed that HPPR- b-ELISA is a suitable and valid method that can alternatively be used for screening and monitoring of PPR in sheep, goats and cattle except for camels.

Seroprevalence and associated risk factors of peste des petits ruminants among ovine and caprine in selected districts of Afar region, Ethiopia.

BACKGROUND: A Peste des petits ruminant is an acute, highly contagious and economically important transboundary viral disease of small ruminants. Despite the fact that food and agriculture organization and world organization for animal health plan to eradicate the disease by 2030, some studies indicated an increasing seropositivity of PPR infection in sheep and goats in Ethiopia. A cross-sectional study was employed to estimate the seroprevalence of PPR and to assess risk factors during the study period, February to April, 2020. Following purposive selection of the study districts, simple random sampling technique was employed to select individual animal during sample collection. A total of 384 serum samples were collected from apparently healthy sheep and goats. Competitive Enzyme Linked Immunosorbent Assay was used to detect the presence of antibodies against PPR at national veterinary institute. Descriptive statistics, Pearson's chi-square (X2) and logistic regression analysis were used is this study. RESULTS: The overall animal level seroprevalence of PPR virus was found to be 60.15% (n = 231/384) and species level prevalence rate was found to be 38.18% (n = 42) in sheep and 68.98% (n = 189) in goats in the study areas. Among the associated risk factors considered; species, sex, age and herd sizes were significantly associated (P < 0.05) with the disease occurrence. Among the associated risk factors considered in this study, species, sex, age and herd size were found to be statistically associated with the seropositivity of PPR infection. CONCLUSION: The present study finding revealed that a higher seroprevalence of PPR virus infection and this confirms peste des petits ruminant virus is circulating in Afar region. Further studies should be carried out on the entire region to determine PPR seroprevalence and to develop appropriate control and eradication strategies of PPR disease.

A competitive ELISA for detection of group specific antibody to bluetongue virus using anti-core antibody.

Bluetongue virus (BTV) is transmitted by biting midges, which infects domestic and wild ruminants. In present study, a competitive enzyme-linked immunosorbent assay (C-ELISA) for the detection of serogroup-specific antibodies against VP7 protein of BTV has been developed. The assay measures the competition between a group specific antibody against core protein of BTV and a test serum to an optimized concentration of BTV recombinant-VP7 (r-VP7) antigen. Serum samples (n = 895) collected from small and large ruminants were used to optimize the C-ELISA. Percent inhibition (PI) values were used for estimation of the cut-off value for the C-ELISA. On receiver operator characteristic (ROC) analysis, different cut-off values along with their diagnostic sensitivity (DSn) and diagnostic specificity (DSp) were obtained. Among these, >50% PI value was accepted as cut-off at which DSn and Dsp was achieved as 97.6% and 98.0% respectively, at >95% confidence interval. Results show the present C-ELISA assay described to be sensitive, specific and reliable and could be adopted for serological investigation of small and large ruminants.

Serosurveillance and factors associated with the presence of antibodies against bluetongue virus in dairy cattle in two eco-zones of Nepal.

Cattle play an important role in the epidemiology of bluetongue (BT) by acting as reservoir hosts. However, the status of BT virus (BTV) in dairy cattle in Nepal is unknown. The objective of this study was to estimate the prevalence of BTV antibodies in dairy cattle in two eco-zones of Nepal, and to identify the factors associated with virus exposure. The authors conducted a cross-sectional serosurvey from March 2012 through February 2013 by sampling 131 dairy cattle from seven clusters (villages) in the Chitwan district in the Terai region (southern lowlands) and the Lamjung district in the Hills region (the middle part of Nepal). Of the 131 serum samples tested, 29.3% (95% confidence interval [CI]: 21.5-37.2) were positive for BTV antibodies. Herd-level seroprevalence was 45.7% (95% CI: 30.9-61.0). Bivariate analysis indicated a positive association between seroconversion to BTV and age, and an association with breed of cattle after controlling for clustering of animals within herds. Based on this model, cattle were more likely to become seropositive as they aged. Crossbred cattle were more likely to be seropositive than those of exotic breeds (odds ratio [OR] = 4.6; 95% CI: 1.5-14.1). The results indicate widespread exposure of dairy cattle to BTV in Nepal. The authors suggest that dairy cattle should be included in the surveillance plan for BTV infection in Nepal and that it is important to educate farmers about the possible impacts of this disease.

Les bovins jouent un rôle important en tant qu'hôtes réservoirs dans l'épidémiologie de la fièvre catarrhale ovine (FCO). Toutefois, au Népal le statut des bovins de races laitières au regard du virus de la FCO était inconnu. La présente étude a été conduite pour estimer la prévalence des anticorps dirigés contre la FCO chez les bovins laitiers dans deux zones écologiques du Népal et pour élucider les facteurs présentant un lien avec l'exposition virale. Les auteurs ont réalisé une enquête sérologique transversale de mars 2012 à février 2013, en prélevant 131 bovins laitiers répartis en sept groupes (villages) du district de Chitwan, région de Terai (plaines méridionales) et du district de Lamjung, région des Collines (centre du Népal). La présence d'anticorps dirigés contre la FCO a été détectée dans 29,3 % des 131 sérums testés (intervalle de confiance [IC] à 95 % : 21,5­37,2). À l'échelle des troupeaux, la prévalence sérologique était de 45,7 % (IC à 95 % : 30,9­61,0). L'analyse bivariée a fait apparaître une corrélation positive entre l'apparition d'anticorps dirigés contre la FCO et l'âge et, après vérification de la répartition des bovins par groupes au sein des troupeaux, une corrélation avec la race. D'après ce modèle, l'apparition d'anticorps devenait plus fréquente à mesure que les bovins prenaient de l'âge. De même, l'apparition d'anticorps était plus fréquente chez les bovins de races croisées que chez les bovins de race exotique (rapport de cotes = 4,6 ; IC à 95 % : 1,5­14,1). Ces résultats font état de l'ampleur de l'exposition des bovins laitiers au virus de la FCO au Népal. Les auteurs préconisent d'intégrer les bovins de races laitières dans le plan de surveillance de l'infection par le virus de la FCO au Népal et de sensibiliser les éleveurs sur les conséquences potentielles de cette maladie.

El ganado vacuno cumple una importante función en la epidemiología de la lengua azul por su intervención como hospedador reservorio. Pese a ello, en el Nepal se desconoce cuál es el estado del ganado lechero en relación con el virus de la enfermedad. Los autores describen un estudio destinado a estimar la prevalencia de anticuerpos contra el virus de la lengua azul en el ganado lechero de dos zonas ecológicas del Nepal y a determinar los factores asociados a la exposición al virus. En primer lugar, entre marzo de 2012 y febrero de 2013, se llevó a cabo un estudio serológico transversal con la obtención de muestras de 131 bovinos lecheros de siete agrupaciones (aldeas) de los distritos de Chitwan, región de Terai (vegas meridionales), y de Lamjung, región de las Colinas (en la zona central del país). De las 131 muestras de suero analizadas, resultaron positivas para los anticuerpos contra el virus de la lengua azul el 29,3% (intervalo de confianza [IC] al 95%: 21,5­37,2). La seroprevalencia de rebaño se cifraba en un 45,7% (IC 95%: 30,9­61,0). El análisis de dos variables puso de manifiesto una correlación positiva entre la seroconversión contra el virus de la lengua azul y la edad, así como una asociación con la raza del ganado, previo control de las agrupaciones de animales dentro de los rebaños. Según se desprende de este modelo, la probabilidad de que el ganado pase a ser positivo aumenta con la edad. Los animales de raza híbrida presentan mayor probabilidad de ser seropositivos que los de razas exóticas (razón de probabilidades = 4,6; IC 95%: 1,5­14,1). Estos resultados ponen de relieve una extendida exposición al virus en el ganado lechero nepalí. Los autores preconizan la inclusión del ganado vacuno lechero en el plan de vigilancia de la infección por el virus de la lengua azul en el Nepal y recalcan la importancia de hacer pedagogía entre los ganaderos acerca de las posibles repercusiones de la enfermedad.

Prevalence of contagious caprine pleuro-pneumonia in pastoral flocks of goats in the Rift Valley region of Kenya.

A cross-sectional survey was conducted between the months of March 2014 and March 2015 to determine the prevalence of contagious caprine pleuropneumonia in goat populations in pastoral flocks in three sub-counties of the Rift Valley region. A total of 432 serum samples were collected from goats from 54 flocks and tested for the presence of antibodies against mycoplasma capricolum subspecies capripneumoniae (mccp) using monoclonal antibody-based competitive enzyme-linked immuno-sorbent assay. Sero-prevalence recorded for Turkana West was 63.9%, Kajiado Central was 48.6%, while Pokot East was 29.2% which was statistically significant (χ2 = 34.997; P = 0.000) in the study sites. The results of this study confirmed that CCPP is widespread and endemic in the pastoral production systems studied in the Rift Valley region. The results confirmed that regions sharing international boundaries are at a higher risk of CCPP hence the need for a unified cross-border approach to disease control measures in the border areas.

Automatic offline-capable smartphone paper-based microfluidic device for efficient biomarker detection of Alzheimer's disease.

BACKGROUND: Alzheimer's disease (AD) is a prevalent neurodegenerative disease with no effective treatment. Efficient and rapid detection plays a crucial role in mitigating and managing AD progression. Deep learning-assisted smartphone-based microfluidic paper analysis devices (µPADs) offer the advantages of low cost, good sensitivity, and rapid detection, providing a strategic pathway to address large-scale disease screening in resource-limited areas. However, existing smartphone-based detection platforms usually rely on large devices or cloud servers for data transfer and processing. Additionally, the implementation of automated colorimetric enzyme-linked immunoassay (c-ELISA) on µPADs can further facilitate the realization of smartphone µPADs platforms for efficient disease detection. RESULTS: This paper introduces a new deep learning-assisted offline smartphone platform for early AD screening, offering rapid disease detection in low-resource areas. The proposed platform features a simple mechanical rotating structure controlled by a smartphone, enabling fully automated c-ELISA on µPADs. Our platform successfully applied sandwich c-ELISA for detecting the ß-amyloid peptide 1-42 (Aß 1-42, a crucial AD biomarker) and demonstrated its efficacy in 38 artificial plasma samples (healthy: 19, unhealthy: 19, N = 6). Moreover, we employed the YOLOv5 deep learning model and achieved an impressive 97 % accuracy on a dataset of 1824 images, which is 10.16 % higher than the traditional method of curve-fitting results. The trained YOLOv5 model was seamlessly integrated into the smartphone using the NCNN (Tencent's Neural Network Inference Framework), enabling deep learning-assisted offline detection. A user-friendly smartphone application was developed to control the entire process, realizing a streamlined "samples in, answers out" approach. SIGNIFICANCE: This deep learning-assisted, low-cost, user-friendly, highly stable, and rapid-response automated offline smartphone-based detection platform represents a good advancement in point-of-care testing (POCT). Moreover, our platform provides a feasible approach for efficient AD detection by examining the level of Aß 1-42, particularly in areas with low resources and limited communication infrastructure.

Evaluation of three serological tests for the diagnosis of Brucella suis in dogs using Bayesian latent class analysis.

Brucella suis infection of dogs is an emerging issue worldwide requiring specific management to address zoonotic risks and animal welfare concerns. Diagnosis in dogs is routinely based on serological testing, but to date these tests have only been validated for use in production animal species and humans. This study aimed to assess the diagnostic performance of three commonly used serological tests in dogs. Canine sera (n = 989) were tested with the Rose Bengal rapid plate agglutination test (RBRPT), the complement fixation test (CFT) and a competitive ELISA (C-ELISA). Diagnostic test performance was evaluated using a three test, two population Bayesian latent class analysis accounting for conditional dependence between the three tests. Positive and negative predictive values (PPV, NPV) were calculated for a range of expected prevalence estimates for the individual tests and test combinations interpreted in series and parallel. The RBRPT showed the highest individual Se of 0.902 (95 % posterior credible interval [PCI] 0.759-0.978) and the CFT the highest individual diagnostic specificity (Sp) of 0.914 (95 % PCI 0.886-0.946). The C-ELISA had marginally the best overall diagnostic performance (Youden's index = 0.807). The CFT and the C-ELISA interpreted in parallel returned the highest combined Se and Sp (0.988 and 0.885, respectively). All tests returned NPVs of > 0.982 in 2-8 % prevalence settings. Series interpretation of the three-test combination as well as the two-test combinations of the RBRPT and the C-ELISA and the CFT and the C-ELISA produced a PPV of 0.502 when the estimated prevalence was 8 %. While all tests are suitable for the detection of B. suis antibodies in dogs, they should not be interpreted in isolation as their diagnostic value is dependent on the pre-test probability of the disease. As such they are useful tools for the diagnosis of B. suis in dogs when exposure, history and clinical presentation indicate a risk of brucellosis.

Serological and molecular surveillance of West Nile virus in domesticated mammals of peninsular Malaysia.

West Nile virus is a mosquito-borne neurotropic pathogen with a wide host range that constitutes a significant risk to public and animal health. There is limited information on WNV infection in domesticated mammals in Malaysia; however, current reports indicate infections in birds, macaques, bats and pigs from Malaysia. In this study, 203 serum samples from cattle, goats, and horses were tested for the presence of anti-WNV IgG using a competitive enzyme-linked immunosorbent assay (c-ELISA). Additionally, using one-step RT-PCR, nasopharyngeal swabs were analyzed for WNV RNA from all 203 animals in this study. The WNV seroprevalence was 32.53% (27/83) at 95% CI (0.2342-0.4319) in cattle, 48.27% (14/29) at 95% CI (0.3139-0.6557) in goats and 53.84% (49/91) at 95% CI (0.4366-0.6373) in horses. Cross-reactive JEV antibodies were detected in two cattle and 34 horses. None of the cattle or goats tested positive for WNV RT-PCR. Seven horses were positive for WNV RT-PCR, a molecular prevalence of 7.69% (7/91) at 95% CI (0.0353-0.1528). This is the first reported detection of WNV in domesticated mammals of Malaysia, a significant addition to the growing evidence that WNV is being transmitted from vectors to susceptible hosts in Malaysia.

Seroprevalence and Risk Factors Related to Bovine Brucellosis in Continental Ecuador.

Bovine brucellosis is a worldwide zoonotic contagious disease. According to World Animal Health Information System reports Ecuador has presented an increasing number of bovine brucellosis outbreaks in the continental territory over the past years (756 in 2018 versus 964 in 2021), generating economic losses for producers and causing a risk to public health. A cross-sectional study was conducted to investigate the seroprevalence of bovine brucellosis and associated risk or protective factors between May and June 2018. This stratified random study was implemented in 290 cattle herds located in the 23 provinces of continental Ecuador, which represents a total of 3737 cows aged 24 months or older. A competitive ELISA was used to detect Brucella antibodies. Simultaneously, an epidemiological survey was implemented to assess the brucellosis risk or protective factors. The apparent prevalence of bovine brucellosis at the herd level was 21.3% (95% CI: 16.8-26.6) and 6.2% (95% CI: 5.5-7) at the animal level. Univariate and multivariate logistic regression analyses were performed to determine the relationship between the potential factors associated with the presence of bovine brucellosis. The risk factors identified after multivariate analysis were a surface in ha per herd > 70 ha (OR = 2.73; 95% CI: 1.18-6.32) and the number of parturitions per animal (two or more with OR ≥ 1.8 and p-value ≤ 0.047). On the contrary, the protective factors were the region (farms located in the eastern region) and the absence of reported clinical signs. In addition, in herds where extensive production predominates, farmers have a low level of knowledge, and the farm biosecurity level is low. These results can guide the authorities in managing the risk factors identified, understanding the current epidemiological situation in Ecuador, improving the bovine brucellosis control program and food safety, as well as increase the one-health approach.

Peste des petits ruminants virus antibodies in domestic large ruminants in Bangladesh.

INTRODUCTION: Peste des petits ruminants (PPR) is an important transboundary animal disease of small ruminants which causes serious damage to the livelihood and food security of millions of small-scale farmers. PPR is endemic in goats in Bangladesh since 1993. The aim of this study was to determine the seroprevalence of PPR in sheep, cattle, and buffaloes in Bangladesh. METHODOLOGY: A total of 434 blood samples from sheep (n = 100), cattle (n = 190) and buffalo (n = 144) were collected aseptically. Sera were separated and antibody titer was determined using a commercially available c-ELISA kit. RESULTS: The overall seroprevalence was 16% and 3.68% in sheep and cattle, respectively, while buffaloes had a considerably higher seroprevalence of 42.36%. The study suggests that buffaloes are more prone to the PPR virus (PPRV) infection and cattle. CONCLUSIONS: This study provides serological evidence of PPRV infection in cattle and buffaloes. These results may warrant further studies to find out the role of large ruminants in transmitting PPRV infection to small ruminants and vice versa and inclusion of all domestic and wild ruminants for regular surveillance program.