Yuvaluk Khoprasert

Plant Protection Research and Development Office Thailand

BACKGROUND Upon request of the local administration a control campaign targeting commensal rats (Rattus rattus, R. exulans) was conducted in 30 sub‐districts (villages) of the World Heritage town Luang Prabang, Northern Laos, using rat bait containing lethal quantities of the parasitic protist Sarcocystis singaporensis. The associated investigation...

Here we present results of a campaign of biological rodent control in the World Heritage town of Luang Prabang in Northern Laos that was implemented in 30 sub-districts ('villages') or 3,706 households, which constituted a large part protected under UNESCO (about 197 ha). Rat bait containing lethal quantities of the parasitic protist Sarcocystis si...

We examined Sarcocystis spp. in giant snakes from the Indo-Australian Archipelago and Australia using a combination of morphological (size of sporocyst) and molecular analyses. We amplified by PCR nuclear 18S rDNA from single sporocysts in order to detect mixed infections and unequivocally assign the retrieved sequences to the corresponding parasit...

Sarcocystis singaporensis is a parasitic protozoan native to southeast Asia, which cycles between the reticulated python and rodents of the genera Rattus and Bandicota to sustain its life. Since 2001, a formulation containing live parasites in various life stages is being commercialized for rodent control in various Southeast Asian countries after...

A field and a household survey, the latter of which included inspections and interviews with the residents of a total of 1370 properties, were conducted in 2004 in 30 villages of the city of Luang Prabang, Lao PDR, in order to assess the degree of rodent infestation and to identify potential factors influencing infestations. Roof rats, Rattus rattu...

Biological rodent control using the parasitic protozoan Sarcocystis singaporensis has been shown to be effective in various crops. As the parasite multiplies in endothelial cells of the rat, a potential synergism between infection and anticoagulant rodenticides was anticipated. Subsequent laboratory experiments confirmed that combination of subleth...

Phylogenetic investigations, sequence comparisons, and antigenic cross-reactivity studies confirmed the classification of Thailand virus (THAIV) as a distinct hantavirus species. The examination of sera from 402 rodents trapped in 19 provinces of Thailand revealed that five greater bandicoot rats (Bandicota indica) and one lesser bandicoot rat (B....

Replicated large-scale field trials in two seasons in Thailand with the protozoan parasite Sarcocystis singaporensis showed that damage due to rats was reduced significantly. Biological as well as conventional (local practice using electric fences and zinc phosphide) rodent control reduced the mean proportion of rat-cut tillers in the first (biolog...

During 1999-2000, kidney tissues of approximately 15% of 1310 rodents trapped from northeastern provinces of Thailand were tested for the presence of leptospires. Our direct immunofluorescent assay (DFA) for detection of leptospires showed 100% sensitivity and 94% specificity with the culture data. Both methods identified R. norvegicus as the highe...

There is a great deal of concern regarding the hazard potential of human exposure to toxic substances and carcinogens as well as infectious agents in the environment. For monitoring purposes fish are well established with regard to aquatic pollution. However, for the human environment, mammalian species might be considered more relevant. As the var...

Parasite virulence (pathogenicity depending on inoculum size) and host immune reactions were examined for the apicomplexan protozoan Sarcocystis singaporensis. This parasite is endemic in southeastern Asia and multiplies as a proliferation (merozoite) and transmission stage (bradyzoite) in rats. Virulence in wild brown rats of parasites freshly iso...

Immunoglobulin subclass responses of wild brown rats (Rattus norvegicus) from southeastern Asia to the endemic cyst-forming coccidian Sarcocystis singaporensis were characterised. The antibody response of brown rats to wild-type parasites (high reproductive capacity) showed a Th1 profile during acute infection, namely elevated concentrations of par...

Rodents are known to host numerous pathogens that are harmful to humans. To date, almost nothing is known about the extent to which the immune system of wild rodents responds to these pathogenic organisms. Knowledge of the immune status of rodents could reveal insights into the epidemiological importance of certain species as transmitters of diseas...

Parasites have been identified as an important factor in regulating vertebrate populations. In replicated field experiments (plots up to 4 ha) performed in Thailand we tested whether commensal and field rodents could be artificially infected and controlled with the host-restricted apicomplexan protozoon Sarcocystis singaporensis which is endemic in...

Thailand is an agricultural country where rice and other agricultural products contribute a substantial part to the gross domestic product. Rodents cause problems both in agriculture and as reservoirs of human diseases. Some basic data on the agricultural situation in Thailand and the damage inflicted by rodents as well as an overview of past and p...

One to six Sarcocystis spp. were identified in the skeletal muscles of 41 (33%) of 124 wild rodents (Rattus spp. and Bandicota indica) mainly captured in the central plains of Thailand throughout the year in 1995. Included were S. singaporensis, S. villivillosi, and S. murinotechis-like cysts all of which showed a striated cyst wall at the light mi...