High prevalence of caprine arthritis encephalitis virus (CAEV) in Taiwan revealed by large-scale serological survey

Seroprevalence and contributing factors of transboundary animal diseases in sheep and goats: a study in Peninsular Malaysia

Diseases caused by small ruminant lentiviruses, Mycobacterium avium ssp. paratuberculosis (MAP), Schmallenberg virus, and peste des petits ruminants virus (PPR) is globally recognised as serious threats to the ruminant industry due to their potential to spread rapidly across boundaries. Despite their global distribution and negative impacts on ruminant production, there is a gap in knowledge of the current trends in their epidemiology among sheep and goat populations in Peninsular Malaysia. This study was therefore designed to fill the gap of knowledge concerning the seroprevalence and contributing factors of CAEV, paratuberculosis, SBV, and PPRV among small ruminants from selected flocks in Selangor, Negeri Sembilan, and Pahang states in Peninsular Malaysia. A cross-sectional study design was used to collect animal data and blood samples for serological assays simultaneously. The ID Screen (ID.VET, France) indirect ELISA screening tests were used to detect serum antibodies directed against CAEV/MVV (VISNAS Ver 0922), paratuberculosis (PARAS Ver 0516), SBV (SBVC Ver 1114) and PPRV (PPRC Ver 0821). There was 45.4% (95% CI = 40.74-50.74), 6.8% (95% CI = 4.66-9.69), 27.8% (95% CI = 23.35-32.77), and 2.6% (95% CI = 1.11-0.51) true seroprevalence for CAEV, paratuberculosis, SBV, and PPR, respectively. Geographical location and species were the risk factors for CAEV and paratuberculosis, while the management system and age of small ruminants were the risk factors for SBV. The present study is the first to document a large-scale seroprevalence of MAP and PPR infection among sheep and goat flocks in Peninsular Malaysia. The presence of PPRV and MAP antibodies among small ruminant flocks is signalling current or previous exposure to the pathogens or cross reactions with similar antigens. This finding further suggests the potential for future outbreaks of these devastating diseases among sheep and goats in Malaysia. The high seroprevalence of CAEV and SBV among small ruminants indicates high levels of exposure to the viruses in the environment, which is a potential threat to production.

High positivity rate of caprine arthritis encephalitis virus in Luzon, the Philippines revealed by nested-polymerase chain reaction assay

Caprine arthritis encephalitis (CAE) is a worldwide economically important disease of small ruminants particularly goats. CAE has been considered to be an emerging/re-emerging disease of goats and a notifiable disease in the Philippines. In this study, a nested-PCR method to detect CAE virus (CAEv) infection was conducted between January 2021 to December 2022. A total of 1334 goat blood samples were collected from 24 goat farms throughout Luzon, the Philippines. The over-all prevalence rate was 31.41% (419/1334) in goats and 91.67% (22/24) of goat farms. These results showed high positivity rate of CAEv and the disease may be widespread in Luzon, the Philippines.

Case Report: A Case of Caprine Arthritis Encephalitis in Dairy Goat Farms in South Korea

One Saanen dairy goat (Capra aegagrus hircus) farm in Korea reported that some goats showed clinical signs such as arthritis, paralysis, carpal joint swelling, and even death. We monitored clinical signs and pathological lesions. In the laboratory, we confirmed caprine arthritis encephalitis virus (CAEV) infection by polymerase chain reaction (PCR). We examined all the dairy goats on the farm and found that many of them were positive. In conclusion, CAEV infection was detected in the majority of the goats in this farm, and it induced severe clinical signs impacting productivity and causing important economic shortfalls. We need to regularly investigate all dairy goat farms, and, more importantly, inspection of the quarantine stage should be required before importation. Interestingly, we found all negative results in Korean native black goats (Capra hircus linnaeus).

Initial multi-target approach shows importance of improved caprine arthritis-encephalitis virus control program in Russia for hobbyist goat farms

Background and Aim:

Several reports described the detection of specific caprine arthritis-encephalitis virus (CAEV) antibodies in Russian goat populations, which indicates the circulation of CAEV in Russian goat farms. The aim of this study was to use a multi-target approach to testing with both serological tests and an in-house real-time (RT) molecular test to investigate the prevalence of CAEV in goats from three hobbyist farms in the Republic of Tatarstan, Russia.

Materials and Methods:

We applied a multi-target approach to testing with both enzyme-linked immunosorbent assay (ELISA) and an in-house RT polymerase chain reaction test to investigate the prevalence of CAEV in goats. Animals from the three hobbyist farms were used in this study. The animals from two farms (n=13 for F1 and n=8 for F2) had clinical signs of arthritis and mastitis. In the third farm (n=15 for F3), all goats were home-bred and had no contact with imported animals.

Results:

CAEV antibodies (ELISA targets TM env and gag genes) were detected in serum samples from two farms (F1 and F2), indicating seroprevalence of 87.50-92.31%. Specific CAEV antibodies were also detected in milk samples. CAEV proviral DNA was detected in 53.85-62.50%. The results from all tests performed in the third farm (F3) were negative, indicating that all tests were 100% specific.

Conclusion:

The results showed that CAEV is circulating and present in small hobbyist goat farms in Russia. Serological and molecular tests could be important for programs to control and eradicate CAEV in Russia for hobbyist goat farms.

Further Insights Into Caprine Arthritis Encephalitis (CAE): The Current Status of Seroprevalence Among Small Ruminants in Two Selected States of Peninsular Malaysia

Caprine arthritis-encephalitis virus (CAEV) is a member of the genus lentivirus causing caprine arthritis-encephalitis (CAE), a chronic inflammatory condition affecting the lungs, joints, udder and central nervous system of small ruminants such as sheep and goats. CAE is distributed worldwide and is recognised as a significant cause of morbidity and decreased milk production in dairy goats. Earlier studies highlighted the clinicopathological features and supplied preliminary serological evidence for the existence of CAE among selected goat herds in Malaysia. Therefore, this study aims to provide further insights into the seroprevalence and contributing factors of CAE among sheep and goat herds in two states of Peninsular Malaysia. The blood samples and biodata were randomly collected from a total of 262 individual sheep (40) and goat (222) in seven smallholder farms. Blood sera were tested for specific anti-CAEV antibodies using Qayee-Bio CAEV sandwich-ELISA test kits according to standard procedures. Our results of the study revealed 21.4% (95% CI: 15.8-28.6) apparent and 20.6% (95% CI: 14.5-27.8) true seroprevalence with significant differences (p < 0.05) in seroconversion rates between the states, farms, production systems and breeds of small ruminants. The prevalence of CAE in the Malaysian Peninsular is a potential threat to the small ruminant industry and developing agricultural economy. Further studies are required to determine the genetic characteristics, distribution and risk factors of CAEV for effective prevention and control in Malaysia.

Caprine Arthritis Encephalitis Virus Disease Modelling Review

Simple Summary

Mathematical modelling is used in disease studies to assess their economical impacts, as well as to better understand the epidemiological dynamics of the biological and environmental factors associated with disease spreading. For an incurable disease such as Caprine Arthritis Encephalitis, this knowledge is extremely valuable. However, the application of modelling techniques to study this disease has not been significantly explored in the literature. The purpose of the present work was to review the published studies, highlighting their scope, strengths and limitations, as well to provide ideas for future modelling approaches for this disease. The reviewed studies were divided into two major themes. The first is epidemiological modelling, which use mathematical models which equations describe the disease dynamics over time. Inside this group, the articles differ in considering or not considering the sexual transmission component. The second major theme is statistical modelling, which correlates the disease with biological and environmental factors to quantify its risks and impacts. Inside this group, the articles include models for dairy production, for risk factors of the disease and for Caprine Arthritis Encephalitis being a risk factor for other diseases. Finally, the present work concludes with further suggestions for modelling studies on Caprine Arthritis Encephalitis.

Abstract

Mathematical modelling is used in disease studies to assess the economical impacts of diseases, as well as to better understand the epidemiological dynamics of the biological and environmental factors that are associated with disease spreading. For an incurable disease such as Caprine Arthritis Encephalitis (CAE), this knowledge is extremely valuable. However, the application of modelling techniques to CAE disease studies has not been significantly explored in the literature. The purpose of the present work was to review the published studies, highlighting their scope, strengths and limitations, as well to provide ideas for future modelling approaches for studying CAE disease. The reviewed studies were divided into the following two major themes: Mathematical epidemiological modelling and statistical modelling. Regarding the epidemiological modelling studies, two groups of models have been addressed in the literature: With and without the sexual transmission component. Regarding the statistical modelling studies, the reviewed articles varied on modelling assumptions and goals. These studies modelled the dairy production, the CAE risk factors and the hypothesis of CAE being a risk factor for other diseases. Finally, the present work concludes with further suggestions for modelling studies on CAE.

The epidemiological background of small ruminant lentivirus infection in goats from Romania

Background and Aim:

Caprine arthritis-encephalitis (CAE) is an economically significant viral disease of goats caused by a small ruminant lentivirus (SRLV) belonging to Retroviridae family. This study aimed to summarize current information on the epidemiological status of SRLVs infection in the population of goats from Romania and to point out the CAE incidence throughout the 2008-2018 periods.

Materials and Methods:

An exhaustive review of the papers published in the international literature concerning the epidemiological status of CAE in Romania was carried out using electronic databases, and available statistical data from the World Organization for Animal Health (OIE) regarding the incidence of the disease between 2008 and 2018 were analyzed.

Results:

The true individual-level seroprevalence of CAE was estimated in 13 of 42 counties (31%) and ranged from 0.4% to roughly 40%. One hundred eighty-two outbreaks from 14 counties (33%) were reported, with a peak in 2010.

Conclusion:

The findings sourcing in the literature are very scarce and show disagreement with the situation reported by the national veterinary authorities. Lack of SRLVs screening policies represents the main obstacle in limiting the spread of the disease. Romania’s National Sanitary Veterinary and Food Safety Authority should implement a program for diagnosis and surveillance of the disease to build a straightforward epidemiological picture that represents a prerequisite of any control and eradication program.

Short communication: Genetic parameter estimates for caprine arthritis encephalitis in dairy goats

Caprine arthritis encephalitis (CAE) is a chronic disease caused by a retrovirus from the Lentivirus genus. No effective vaccines or treatments exist, and therefore genetic selection for CAE resistance might be a feasible alternative. To our best knowledge, no other studies have investigated the genetic architecture of CAE resistance in dairy goats. In this context, this study was designed to estimate genetic parameters for CAE infection in Alpine and Saanen goats using a Bayesian threshold model. A total of 542 adult goats (and >3-generation pedigree), which were group-housed in a population with high CAE prevalence, were tested based on a serological infection assessment test (negative = 1 or positive = 2) and used for this study. Genetic parameters were estimated using the BLUPF90 family programs. There was considerable genetic variability for CAE resistance, and pedigree-based heritability was significantly different from zero (0.026 < heritability < 0.128). Our findings indicate that the prevalence of CAE in goat herds can be reduced or eliminated through direct genetic selection for CAE resistance in addition to proper management strategies.

Small ruminant lentiviruses in goats in southern Italy: Serological evidence, risk factors and implementation of control programs

Small ruminant lentiviruses (SRLVs) can drastically affect milk production in goat flocks and only an early detection can control and prevent their spread. Since SRLVs are responsible for persistent infections, antibody screening is the most valuable tool to identify infected animals. ELISA is recommended as the election test both for its sensitivity and for its ability to detect low antibody titers, thus identifying infected animals earlier than agar gel immunodiffusion (AGID). In the present study, an investigation was conducted to assess the SRLV seroprevalence in goat flocks in southern Italy and a transversal comparative study was carried out through the analysis of the possible risk factors influencing SRLV spread. A total of 4800 sera from 1060 flocks were analyzed and overall seroprevalences of 18,64% and 51,69% at animal and herd levels, respectively, were observed. Both the region and the herd production systems were able to affect seroprevalence, differently from the herd size, probably because the mean number of goats per herd is low and the semi-intensive management is similar regardless of the dimensional class of each herd. In particular, meat producing herds showed the higher seroprevalence, as a result of the poor sanitation and low animal monitoring in comparison to milk producing herds, where animals are managed twice daily and the relationship between dams and kids is checked to guarantee an adequate quantitative/qualitative milk yield. In the absence of vaccines or effective treatments, health preventive management and seroepidemiological investigations are the only successful approach to restrict SRLV spread as observed in countries were official/voluntary control programs are carried out.