Lambs with the Major Histocompatibility Complex DRB1*1101 allele have been shown to produce fewer nematode eggs following natural and deliberate infection. These sheep also possess fewer adult Teladorsagia circumcincta than sheep with alternative alleles at the DRB1 locus. However, it is unclear if this allele is responsible for the reduced egg counts or merely acts as a marker for a linked gene. This study defined the MHC haplotypes in a population of naturally infected Scottish Blackface sheep by PCR amplification and sequencing, and examined the associations between MHC haplotypes and faecal egg counts by generalised linear mixed modelling. The DRB1*1101 allele occurred predominately on one haplotype and a comparison of haplotypes indicated that the causal mutation or mutations occurred in or around this locus. Additional comparisons with another resistant haplotype indicated that mutations in or around the DQB2*GU191460 allele were also responsible for resistance to nematode infections. Further analyses identified six amino acid substitutions in the antigen binding site of DRB1*1101 that were significantly associated with reductions in the numbers of adult T. circumcincta.
Gastrointestinal nematodes can cause assorted health problems to human and other primates. The status of gastrointestinal nematodes in non-human primates remained less documented in Malaysia. This study aimed to determine the occurrence of gastrointestinal nematodes recovered from the fecal samples of captive non-human primates at the Matang Wildlife Centre (MWC), Sarawak. Fresh fecal samples were collected from 60 non-human primates of six species (i.e. Orangutan, Bornean gibbon, Silvered Leaf monkey, Slow loris, Pig-tailed macaque, and Long-tailed macaque) and processed using simple fecal floatation method and fecal sedimentation method. This study shows high prevalence of nematode infection (>=50%) and co-infection (22 from 45 infected individuals) in all species of captive non-human primates found in MWC, except one individual of young Silvered Leaf monkey was negative for nematode. From these, eight genera of 11 species and one unknown nematode larvae were recovered and among them Oesophagostomum sp., Ascaris sp., and Strongyloides sp. were the most common nematodes infecting the non-human primates. All the Bornean gibbon (n=7) were found to be infected with nematodes. Moreover, Long-tailed macaques at the centre were heavily infected by Ascaris sp. (number of total count, nt = 2132; total mean abundance, MA=113.70). This is the first report of high prevalence nematode infection on multiple species of captive non-human primates in a wildlife centre located in Sarawak. Some of the nematodes are of zoonotic potential. This information is important for health care management, both in-situ and ex-situ conservations of captive and free-ranging nonhuman primates.
Gastrointestinal nematode infection is one of the major diseases affecting small ruminants. Although some breeds of goats are quite resistant, many breeds of goats are relatively susceptible. This study used a combined parasitological, immunological, bioinformatic and statistical approach to examine the role of goat IgA and eosinophils in protection against Teladorsagia circumcincta. Molecular modelling suggested that the transmembrane domain of the high affinity IgA receptor was dysfunctional in goats. Statistical analyses failed to find any association in naturally infected goats between high IgA or eosinophil responses and low faecal egg counts. Together these results indicate that IgA and eosinophil responses against T. circumcincta are less effective in goats than sheep.
Haemonchosis is a common problem on goat farms in tropical countries such as Malaysia. Prevention of production losses generally depends on the use of anthelmintic drugs, but is threatened by the emergence of anthelmintic resistance. This study investigates anthelmintic efficacy on small-scale Malaysian goat farms and describes putative risk factors. Adult goats had moderate to high pre-treatment faecal trichostrongyle egg counts, despite being housed on slatted floors and fed on cut-and-carry forage, raising questions about the source of nematode infection. Our results show multiple resistance to benzimidazole and macrocyclic lactone anthelmintic drugs and allow us to discuss the genetic origins of resistance with reference to farm husbandry and management. We conclude that improvement in Malaysian goat production efficiency will require the development of sustainable helminth control strategies, underpinned by a better understanding of the origins and population genetics of anthelmintic resistance.
The approaches of transcriptomic and proteomic have been widely used to study host-pathogen interactions in fish diseases, and this is comparable to the recently emerging application of metabolomic in elucidating disease-resistant mechanisms in fish that gives new insight into potential therapeutic strategies to improve fish health. Metabolomic is defined as the large-scale study of all metabolites within an organism and represents the frontline in the 'omics' approaches, providing direct information on the metabolic responses and perturbations in metabolic pathways. In this review, the current research in infectious fish diseases using metabolomic approach will be summarized. The metabolomic approach in economically important fish infected with viruses, bacteria and nematodes will also be discussed. The potential of the metabolomic approach for management of these infectious diseases as well as the challenges and the limitations of metabolomic in fish disease studies will be explored. Current review highlights the impacts of metabolomic studies in infectious fish diseases, which proposed the potential of new therapeutic strategies to enhance disease resistance in fish.
A study was conducted to determine the helminthes in dog's feces and soil samples from urban and rural areas. Six species of nematodes (Toxocara sp, an undetermined nematode larvae, Strongyloides sp larvae, Ascaris sp ova, hookworm ova, Trichuris sp ova) and one species of Cestode (Taenia sp) were found in 175 stool samples. Seventy-eight point nine percent of stool samples were positive for helminthes. Mixed infection with at least one parasite was found in 32.6% of the samples. The prevalence of helminth infection ranged from 1.1% to 45.1%. The prevalence of hookworm sp was the highest with 45.1%. The highest prevalence in urban dogs was hookworm sp in 76.7% and in rural areas was Ascaris sp in 48.7%. Soil samples were also examined to determine contamination of the environment, especially due to Toxocara canis, as a potential source of infection. Urban soil samples showed a higher contamination rate with 26.7% compared to rural areas with 4.9%. Toxocara ova were the most prevalent helminthes contaminating the soil with 12.1%. This study showed that humans from both urban and rural areas are at risk of acquiring helminth infection from contaminated soil.
In a world in which sheep producers are facing increasing problems due to the rapid spread of anthelmintic resistance, the battle against gastrointestinal parasitic nematodes is a difficult one. One of the potential new tools for integrated control strategies is biological control by means of the nematode-destroying microfungus Duddingtonia flagrans. This fungus forms sticky traps that catch developing larval stages of parasitic nematodes in the fecal environment. When resting spores (chlamydospores) of this fungus are fed daily to grazing animals for a period of time, the pasture infectivity and thus, the worm burden of grazing animals are lowered, especially in young lambs. Research has been conducted throughout the world covering many different climates and management systems. An Australian parasite model showed that if the fungus performs efficiently (> or =90% reduction in worm burden) for 2 or 3 mo, it should contribute significantly to a reduction in the number of dead lambs otherwise occurring when managed only by anthelmintic treatment and grazing management. Feeding or field trials have clearly demonstrated that dosing with a few hundred thousand spores per kilogram of live BW not only reduced the number of infective larvae but also increased the BW of the lambs compared with controls not given fungus. Initial Australian work with feeding spores by means of a block formulation or a slow-release device has shown some promise, but further work is needed to fully develop these delivery systems. In tropical Malaysia, small paddock trials and field studies resulted in significant improvements, in terms of lower worm burdens and increased live BW, when feeding half a million spores daily to grazing lambs. Additional benefits have been observed when the fungus is employed in combination with a fast rotational grazing system. Research has also demonstrated that spores can be delivered in slightly moist feed block material, but only if such blocks are consumed rapidly, because of their very short shelf life. In the northern, temperate Danish climate it has been demonstrated that daily feeding of half a million spores per kilogram of live BW can lead to significant production benefits, with increased live BW gain in fungus-exposed animals. Biological control of parasitic nematodes in sheep seems to hold promise for the future, but to be able to assist producers, the optimal delivery system needs to be refined and further developed. In addition, more work will be needed to define the best use of this technology in different geographic regions.
Government-owned small-ruminant breeding farms in Malaysia provide the source of sheep and goats to smallholder farmers in the country. In the eastern Malaysian state of Sabah, high-level stock losses have been recorded on these farms for several years, frequently accompanied by clinical signs indicating pathogenic levels of infections with the nematode parasite Haemonchus contortus. This suggests that their dependence on chemotherapy to control parasite infections had failed. Accordingly, tests for anthelmintic efficacy using the faecal egg count reduction test (FECRT) on the range of drugs used to control nematode parasites were carried out on the five government small-ruminant breeding farms in Sabah. These tests showed a total failure of the benzimidazole, imidothiazole, macrocyclic lactone and salicylanilide groups of anthelmintics to control H. contortus infections of sheep and goats on all farms. Drastic changes in animal management need to be made in an attempt to deal with this situation, for which suggestions are made.
Control of nematode parasites of small ruminants in a wet, tropical environment using the nematophagous fungus, Duddingtonia flagrans, was assessed in this study. Two methods of fungal delivery were tested, namely as a daily feed supplement, or incorporated into feed blocks. Initially, pen trials were conducted with individually penned groups of sheep and goats at dose rates of 125,000 spores and 250,000 spores/kg live weight per day. At the lower dose rate this reduction was between 80 and 90% compared with the pre-treatment levels. At the higher dose rate, there was virtually complete suppression (>99% reduction) of larval recovery. Trials using the fungal feed blocks, showed that when animals were individually penned, they consumed only small amounts of the block (particularly goats), hence little effect on larval recovery in faecal cultures was observed. Grouping animals according to species and dose rate induced satisfactory block consumption and subsequent high levels of larval reduction in faecal cultures. These larval reductions were mirrored by the presence of fungus in faecal cultures. This work was followed by a small paddock trial, whereby three groups of sheep were fed either a feed supplement without fungal spores, supplement with spores, or offered fungal blocks. The dose rate of spores in the latter two groups was 500,000 spores/kg live weight per day. Egg counts were significantly reduced in the two fungal groups, compared with the control group and the latter required two salvage anthelmintic treatments to prevent mortality due to haemonchosis. Pasture larval numbers on the two fungal group plots were also much lower than on the control plot.
Approximately 2,800 fresh dung samples from animals, mainly ruminant livestock, were screened for the presence of nematophagous fungi in Malaysia. Arthrobotrys spp. was noted on numerous occasions, but only one isolate of Duddingtonia flagrans was made. For the purposes of producing sufficient quantities of this fungus for feeding trials in sheep, various, commonly available, cheap plant materials were tested as possible growth substrates. This showed that cereal grains (wheat, millet and rice) were the best media for fungal growth. Pen feeding trials were carried out using sheep, both naturally and experimentally infected with nematode parasites (predominantely Haemonchus contortus), to test the efficiency of D. flagrans when administered either in a grain supplement, or incorporated into a feed block. These showed that the fungus survived gut passage in sheep and that dose rates of approximately 1 x 10(6) D. flagrans spores / animal / day, reduced the percentage of infective larvae developing in faecal cultures by more than 90%. These results indicate that using D. flagrans as a biological control agent of nematode parasites, is a promising alternative to nematode parasite control of small ruminants in Malaysia, where anthelmintic resistance is now a major problem.
Five species of adult nematodes, unidentifiable nematode larvae, and three species of acanthocephalans, were found in freshwater ornamental fishes newly imported into Germany from Brazil, Colombia, Indonesia, Malaysia, Nigeria, Peru, Sri Lanka and Thailand. The following species were identified: Adult Nematoda: Pseudocapillaria tomentosa, Capillariidae gen. sp., Dichelyne hartwichi sp. n., Procamallanus (Spirocamallanus) pintoi and Spinitectus allaeri; Acanthocephala: Pseudogorgorhynchus arii gen. et sp. n., Neoechinorhynchus sp. and Pallisentis sp. The nematode Dichelyne hartwichi sp. n. (male only) from the intestine of Chelonodon fluviatilis (Hamilton) from Thailand is characterised mainly by the presence of minute cuticular spines on the tail tip, length of spicules (510 microns) and arrangement of caudal papillae. The acanthocephalan Pseudogorgorhynchus arii sp. n. from the intestine of Ariopsis seemanni (Günther) from Colombia represents a new genus Pseudogorgorhynchus gen. n., differing from other genera of the Rhadinorhynchidae mainly in possessing a small proboscis armed with markedly few (18) hooks arranged in six spiral rows. Spinitectus macheirus Boomker et Puylaert, 1994 and Spinitectus moraveci Boomker et Puylaert, 1994 are considered junior synonyms of Spinitectus allaeri Campana-Rouget, 1961.
The synlophe of Batrachonema synaptospicula Yuen, 1965 collected from Rana limnocharis Boie, 1835 of peninsular Malaysia was found to be identical morphologically to that in the specimens from Rana narina Stejneger, 1901 of Okinawa, and R. limnocharis of Taiwan. In the midbody, 20-22 ridges are present, and the ridges increase gradually in size and are oriented from right to left in the dorsal and left ventral fields, whereas the right ventral ridges are small and almost perpendicular to the body wall. The orientation of ridges from right to left is considered to be a key characteristic of the genus Batrachonema. Because Amphibiophilus ranae Wang et al., 1978 and Amphibiophilus sp. from R. limnocharis of south China are regarded to be conspecific with B. synaptospicula, this nematode is surmised to be distributed widely in southeast and east Asia.
Faecal samples were collected from 48 randomly selected smallholder goat farms in northern Peninsular Malaysia. The nematode eggs extracted were tested for resistance to thiabendazole using the egg hatch assay technique. Thiabendazole resistance was found on 19% of farms tested.
A new nematode species, Paraphilometroides nemipteri sp. n. is described from the female specimens collected from the dorsal fin and operculum of the marine perciforme fish, Nemipterus peronii off Kuala Terengganu coastal waters in Malaysia. It considerably differs from all other species in Philometridae in the structure of the head end (presence of wide dorsal and ventral cephalic cuticular alae supported by special inner transverse muscular formations) and, therefore, a new genus Paraphilometroides gen. n. has been erected to accommodate it. Additional characteristic features of P. nemipteri are the presence of cuticular bosses on the body, eight cephalic papillae in the outer circle and four small papillae in the inner circle, and the absence of caudal protrusions.
Splenic nodules from 38 cynomolgus monkeys (Macaca fascicularis) which were captured in Malaysia and Indonesia were studied histologically. The lesions were characterized by well-circumscribed focal fibrosis, accumulation of eosinophils and histiocytes, hemorrhage or hemosiderosis, and loss of normal splenic architecture. Small arteries in the lesion frequently had intimal thickening and narrowing of the lumen in addition to the presence of microfilariae. Microfilariae were also seen in the extravascular area of the lesion, and were occasionally engulfed by multinucleated giant cells. The splenic lesion was thought to have been initiated by incomplete infarction caused by intimal thickening and microfilarial occupation of the small arteries.
The histopathology of gastric papillomas in 17 crab-eating monkeys from Indonesia and Malaysia was investigated. The changes in the affected mucosa consisted of papillomatous proliferation with accidental heterotopia, desquamation or necrosis of the epithelium associated with eggs or adults of the small nematode Nochtia nochti, inflammatory cell infiltration and haemorrhage or oedema and fibrosis. The primary pathogenic effect of this parasite was due to its irritant action on the gastric mucosa. Hyper-regeneration, with a downward shift of the proliferating zone in the gastric gland and an inflammatory process, appeared to play a significant role in the morphogenesis of this lesion. It is concluded that the gastric papilloma associated with Nochtia nochti in the monkey is a parasitic inflammatory polyp.
The prevalence of Capillaria hepatica (Bancroft, 1893) infection in a total of 2324 rats trapped from 25 localities in West Malaysia was 15.5%. Infection rates in males (16.0%) and females (15.1%) are similar. A significantly higher percentage of adults (18.1%) than young (7.7%) was infected. Capillaria hepatica infection rates among urban (0.7%) and jungle (0.0%) rats was very low as compared to field rats (17.7%) trapped from agricultural areas such as oil palm estates and rice growing areas. Prevalence of C. hepatica infection in rats is not evenly distributed throughout West Malaysia. There seem to be localised foci of infection. In some areas as many as 77.8% of the adult rats are found to be infected while in other areas the same species of rats are found free of infection.
Capillaria hepatica infection in wild rodents collected from the States of Kelantan, Selangor and Johore in Peninsular Malaysia since 1973 is reported. A total of 1,258 rodents consisting of 20 species of house, field and forest rats, and 7 species of squirrels were examined for the parasite and 17 species consisting of 111 murids and 1 flying squirrel were found infected. The house rat, Rattus norvegicus had the highest prevalence rate, followed by 3 species of field rats, R. tiomanicus, R. argentiventer and Bandicota indica. The prevalence of infection was low among forest rats with the exception of Lenothrix canus. Only 1 flying squirrel, Hylopetes spadiceus was found with the parasite. The prevalence of infection in relation to the host behaviour and habitats was discussed. C. hepatica appears to be widespread throughout Malaysia with a wide range of hosts among rodent species. Some new host records are presented herein.