Lumpy skin disease (LSD) is a highly infectious and economically devastating viral disease of cattle. It is caused by Lumpy Skin Disease Virus (LSDV) belonging to the genus Capripoxvirus and family Poxviridae. The origin of lumpy skin disease has been traced to Zambia, (an African nation) in Southern part during the year 1929. The first reported case of LSD besides Africa was from Israel, a Middle Eastern nation, thus proving inter-continental spread. Subsequently, the disease entered Middle East, Eastern Europe and Asia with numerous outbreaks in the recent years. LSD has emerged as a significant concern in the Indian sub-continent, due to outbreaks reported in countries such as Bangladesh, India, China in 2019. In the following years, other South and East Asian countries like Taipei, Nepal, Sri Lanka, Myanmar, Bhutan, Vietnam, Hong Kong, Thailand, Malaysia, Laos, Cambodia, Pakistan, Indonesia and Singapore also faced severe outbreaks. At present, LSD is considered to be an emerging disease in the Indian sub-continent due to the recent status of disease. Considering the global scenario, LSDV is changing its transmission dynamics as evidenced by a shift in its epidemiology. As a result of high morbidity and mortality rate among cattle, the current outbreaks have been a major cause of socio-economic catastrophe. This contagious viral disease has eminent repercussions as the estimated monetary damage incurred is quite high. Despite having networked surveillance and comprehensive databases, the recurring outbreaks have raised major concern among researchers. Therefore, this review offers brief insights into the emergence of LSDV by amalgamating the newest literature related to its biology, transmission, clinico-pathology, epidemiology, prevention strategies, and economic consequences. Additionally, we have also provided the epidemiological insights of the recent outbreaks with detailed state wise studies.
Newcastle disease (ND) is an extremely contagious and fatal viral disease causing huge economic losses to the poultry industry. Following recent ND outbreaks in Sabah in commercial poultry and backyard farms, it was speculated that this could be due to a new introduction of Newcastle Disease Virus (NDV) genotype/sub-genotype. Here we report the genetic characterization of NDVs isolated from Sabah during early 2021. All isolates were amplified and sequenced with primers specific to the viral fusion (F) gene using reverse transcription-polymerase chain reaction (RT-PCR). Nucleotide sequence analysis of the F gene showed that all isolates shared similar homology of 99.4% with NDV strain from Iran isolated in 2018. Amino acid sequences of the F protein cleavage site revealed the motif of 112RRQKRF117 indicating all isolates were of virulent strain. Phylogenetic analysis demonstrated that all isolates were clustered under sub-genotype VII 1.1 and clustered together with isolates from Iran (previously known as subgenotype VIIl). The present findings suggested that there is an emerging of a new sub-genotype into the poultry population in Sabah and this sub-genotype has never been reported before in Malaysia. Therefore, transboundary monitoring and continuous surveillance should be implemented for proper control and prevention of the disease. A further molecular epidemiological analysis of NDV is needed to well understand the circulatory patterns of virulent strains of NDV in the country to prevent future outbreaks.
Foot-and-mouth disease (FMD) is one of the most important animal diseases hindering livestock production in Thailand. In this study, a temporal and spatial analysis at the subdistrict level was performed on FMD outbreak reports in Thailand from 2011 to 2018. Risk factors associated with FMD outbreaks were furthermore investigated using generalized estimating equations. The results showed that the incidence of FMD outbreaks was the highest in 2016 and was affected by season, with a peak in FMD outbreaks occurring in the rainy-winter season, during October to December. FMD outbreaks were mostly distributed in small clusters within a few subdistricts. Some high-risk areas with repeated outbreaks were detected in the central regions. Risk factors, including the increase of subdistrict's size of the dairy population, beef population or pig population, the low percentage of forest area, subdistricts in the provinces adjacent to Malaysia, the presence of a livestock market and the occurrence of an FMD outbreak in a neighbouring subdistrict in the previous month significantly increased the odds of having an FMD outbreak. The increase in proximity to the nearest subdistrict with an FMD outbreak in the previous month decreased the odds of having FMD outbreaks. This study helped to identify high-risk areas and periods of FMD outbreaks in Thailand. Together with the identified risk factors, its results can be used to optimize the FMD control programme in Thailand and in other countries having a similar livestock industry and FMD situation.
Since the first H5N1 highly pathogenic avian influenza virus (HPAIV) infection in the region in August 2003, Cambodia, Laos, Malaysia, Myanmar, Indonesia, Thailand and Vietnam have all recorded outbreaks of the disease. The HPAIV continues to occur in some countries in Southeast Asia despite control programmes encompassing surveillance, vaccination and stamping out strategies. A number of strains have been circulating in the region since the first outbreaks in 2003, and although the source of the initial outbreaks in domestic poultry is not known, the continuing propagation of disease in the region is primarily the result of the movement of domestic poultry and poultry products, and people. A comprehensive approach using all the strategies available to break the chain of transmission of the virus in poultry will be needed to achieve lasting disease control.
Two related, novel, zoonotic paramyxoviruses have been described recently. Hendra virus was first reported in horses and thence humans in Australia in 1994; Nipah virus was first reported in pigs and thence humans in Malaysia in 1998. Human cases of Nipah virus infection, apparently unassociated with infection in livestock, have been reported in Bangladesh since 2001. Species of fruit bats (genus Pteropus) have been identified as natural hosts of both agents. Anthropogenic changes (habitat loss, hunting) that have impacted the population dynamics of Pteropus species across much of their range are hypothesised to have facilitated emergence. Current strategies for the management of henipaviruses are directed at minimising contact with the natural hosts, monitoring identified intermediate hosts, improving biosecurity on farms, and better disease recognition and diagnosis. Investigation of the emergence and ecology of henipaviruses warrants a broad, cross-disciplinary ecosystem health approach that recognises the critical linkages between human activity, ecological change, and livestock and human health.
The OIE Southeast Asia Foot-and-Mouth Disease Campaign (SEAFMD) involves the coordinated control of foot-and-mouth disease by eight of the ASEAN countries. A long term vision for SEAFMD has been developed and the core element is a progressive zoning approach to the control and eradication of FMD in the region. This paper describes the current status of FMD in Southeast Asia and progress towards achievement of OIE free zone status for FMD in parts of the Philippines and Malaysia and the initiation of the Malaysia-Thailand-Myanmar (MTM) Peninsular Campaign for FMD Freedom. In mainland Southeast Asia, the progressive zoning approach involves several sub-regional groups working in parallel to oversee the epidemiological and economic studies required to determine the feasibility of the approach. Areas involved include the Lower Mekong Basin, Upper Mekong Basin, parts of Myanmar and the Red River Delta of Vietnam. The paper describes the current usage of vaccines for FMD in Southeast Asia and provides recommendations for their supply and use in the new regional initiatives.
Besides response and recovery, prevention and preparedness are the two critical components of any contingency plan. The author discusses the various elements which must be present in the prevention and preparedness plan of countries in Asia. As the continent has such diverse peoples and veterinary infrastructures, the actual plan may vary from one country to another, but must incorporate those elements which are crucial to ensure the success of the preparedness plan.
Meat chickens housed on a commercial broiler farm in Australia were vaccinated once at 10 to 11 days-of-age by aerosol with live V4 Newcastle disease virus (NDV) vaccine. Groups of vaccinated and unvaccinated birds were flown to Malaysia, where they were challenged with a virulent strain of NDV. Survival rates in vaccinated chickens challenged 7, 14, 21 or 31 d after vaccination were 0.47, 0.77, 0.97 and 0.92, respectively. All unvaccinated chickens died due to Newcastle disease (ND) following challenge. Chickens in Australia and Malaysia were bled and the serums tested for haemagglutination-inhibiting (HI) antibody to NDV. Many vaccinated birds with no detectable antibody, and all birds with a log2 titre of 2 or greater, survived challenge. The results showed that this V4 vaccine induced protective immunity in a significant proportion of chickens within 7 d of mass aerosol vaccination. This early immunity occurred in the absence of detectable circulating HI antibody. Non-HI antibody mediated immunity continued to provide protection up to 31 d after vaccination. Almost all vaccinated birds were protected within 3 w of vaccination. It is concluded that the V4 vaccine is efficacious and could be useful during an outbreak of virulent ND in Australia.
An epizootic of measles occurred in a group of 31 silvered leaf-monkeys (Presbytis cristatus) that had been in captivity for 4-12 months. Twenty-four of the monkeys exhibited a maculopapular rash that persisted for 6-9 days. A serous to mucopurulent nasal discharge and conjunctivitis were seen in some animals. Eight monkeys died during the epizootic; however, their deaths could not be directly attributed to measles. Serum samples from the surviving monkeys collected 1-2 months prior to, and 5 weeks after, the epizootic were examined by the complement-fixation and hemagglutination-inhibition tests for antibodies to measles virus. The preepizootic complement-fixation titers were all less than 1:4 and hemagglutination-inhibition titers, less than 1:10. The postepizootic complement-fixation titers in 21 of 23 surviving monkeys ranged from 1:8 to 1:128, and hemagglutination-inhibition titers in 22 of 23 monkeys ranged from 1:40 to 1:80 or greater.
This paper presents investigation of lungworm disease outbreaks that is based on retrospective examination of cases recorded between 1994 and 2000 on a government beef cattle breeding centre in the state of Pahang, peninsular Malaysia. The breed of cattle on the centre was Nelore and the mean population over a 7-year period (from 1994 to 2000) was 1612. All animals were allowed to graze on pasture and mixed grazing was practiced on the farm. The routine de-worming programme was performed using levamisole and ivermectin from 1994 to 1998 and abamectin in 1999 and 2000 on 1 to 3-month-old calves and an annual dose given to the adult cattle. Nelore was introduced into the farm in 1991, three years before the first outbreak from Brazil where Dictyocaulus viviparus infection had been reported. No lungworm infection had been observed in the farm prior to the animal introduction. Within the 7-year period, 36 fatalities occurred and the annual mortality rate due to lungworm infection was 0.31%. The highest rate was recorded in 1997. Among the total 36 deaths, about 75% of deaths occurred in calves aged between 6 months and 12 months, 67% were males and 33% were female cattle. The highest number of deaths (19%) occurred in the month of November. In conclusion, D. viviparus infection may have been introduced into a tropical climate along with consignments of cattle from lungworm endemic areas resulting in fatal disease outbreaks for a few years following the animal's initial introduction.
In connexion with the recent detection of cases of monkeypox in man in West and Central Africa, the frequency of monkeypox outbreaks in monkeys since 1958, when the disease was first recognized in captive animals, has been investigated. Special incidence surveys were made for this purpose. During the last 3 years, a serological survey has been conducted to find natural foci of monkeypox virus, and a total of 2 242 sera from monkeys of different species from various parts of Africa and Asia have been examined for poxvirus antibodies. The survey failed to detect any significant indication of poxvirus infections. The observations suggest that although a few human cases of monkeypox have been identified, monkeypox in the natural environment is not widespread and is perhaps localized in small areas.
Nipah viruses from pigs from a Malaysian 1998 outbreak were isolated and sequenced. At least two different Nipah virus strains, including a previously unreported strain, were identified. The findings highlight the possibility that the Malaysia outbreaks had two origins of Nipah virus infections.
Numerous human diseases, including those caused by viruses like Nipah virus and SARS-CoV, can be traced back to bats as their origin. Malaysia, notably Sabah and Sarawak in Borneo Island, is home to a rich diversity of bats that serve as hosts for various viruses. This comprehensive review represents the inaugural exploration of viruses found in Malaysian bats, as documented in scientific journals. It also encompasses documented instances of bat virus-related disease outbreaks in Malaysia up to the present day, along with an analysis of the risk factors associated with virus spillover events. Furthermore, this review offers insights into prospective research areas of significance and suggests potential mitigation strategies.
Newcastle disease virus remains a constant threat in commercial poultry farms despite intensive vaccination programs. Outbreaks attributed to ND can escalate and spread across farms and states contributing to major economic loss in poultry farms.
An investigation into the epidemiology of Trypansoma evansi infection in crossbred dairy cattle was conducted for a period of 12 months on a dairy cattle farm in Penninsular Malaysia. The prevalence of parasitaemia was highest in lactating animals (13.4%), followed by those in the dry herd (8.8%), late pregnant animals (8.1%), early pregnant animals (4.7%), calves (0.3%) and heifers (0.2%). The prevalence of antigenaemia was highest in the lactating animals (54.7%), followed by that in dry animals (53.7%), heifers (51.1%), late pregnant animals (47.7%), early pregnant animals (46.5%) and calves (24.2%).
The author presents reports of foot and mouth disease (FMD) submitted between 1996 and 2001 to the Office International des Epizooties (OIE: World organisation for animal health) Sub-Commission for FMD in South-East Asia. Of the ten countries in South-East Asia, FMD is endemic in seven (Cambodia, Laos, Malaysia, Myanmar, the Philippines, Thailand and Vietnam) and three are free of the disease (Brunei, Indonesia and Singapore). Part of the Philippines is also recognised internationally as being free of FMD. From 1996 to 2001, serotype O viruses caused outbreaks in all seven of the endemically infected countries. On the mainland, three different type O lineages have been recorded, namely: the South-East Asian (SEA) topotype, the pig-adapted or Cathay topotype and the pan-Asian topotype. Prior to 1999, one group of SEA topotype viruses occurred in the eastern part of the region and another group in the western part. However, in 1999, the pan-Asian lineage was introduced to the region and has become widespread. The Cathay topotype was reported from Vietnam in 1997 and is the only FMD virus currently endemic in the Philippines. Type Asia 1 has never been reported from the Philippines but was reported from all countries on the mainland except Vietnam between 1996 and 2001. Type A virus has not been reported from east of the Mekong River in the past six years and seems to be mainly confined to Thailand with occasional spillover into Malaysia. The distribution and movement of FMD viruses in the region is a reflection of the trade-driven movement of livestock. There is great disparity across the region in the strength and resources of the animal health services and this has a direct impact on FMD control. Regulatory environments are not well developed and enforcement of regulations can be ineffectual. The management of animal movement is quite variable across the region and much market-driven transboundary movement of livestock is unregulated. Formal quarantine approaches are generally not supported by traders or are not available. Vaccination is not used widely as a control tool because of the expense. However, it is applied by the Veterinary Services in Malaysia to control incursions of the disease and there is a mass vaccination programme for large ruminants in Thailand where the Government produces and distributes vaccine. Vaccination is also used by the commercial pig sector, particularly in the Philippines and Thailand.
Eight clones of monoclonal antibodies (Mabs) to Nipah virus (NV) were produced against formalin-inactivated NV antigens. They reacted positive by indirect immunofluorescent antibody test, and one of them also demonstrated virus neutralizing activity. They were classified into six different types based on their biological properties. These Mabs will be useful for immunodiagnosis of NV infections in animals and further research studies involving the genomes and proteins of NV.