Characterization of benzimidazole resistance in Haemonchus contortus: integration of phenotypic, genotypic and proteomic approaches.

The field strain of Haemonchus contortus has a long history of anthelmintic resistance. To understand this phenomenon, the benzimidazole resistance profile was characterized from the Malaysian field-resistant strain by integrating phenotypic, genotypic and proteomic approaches. The faecal egg count reduction test (FECRT) demonstrated that benzimidazole resistance was at a critical level in the studied strain. The primary resistance mechanism was attributed to F200Y mutation in the isotype 1 ß-tubulin gene as revealed by AS-PCR and direct sequencing. Furthermore, the protein response of the resistant strain towards benzimidazole (i.e., albendazole) treatment was investigated via two-dimensional difference gel electrophoresis (2D-DIGE) and tandem liquid chromatography-mass spectrometry (LC-MS/MS). These investigations illustrated an up-regulation of antioxidant (i.e., ATP-binding region and heat-shock protein 90, superoxide dismutase) and metabolic (i.e., glutamate dehydrogenase) enzymes and down-regulation of glutathione S-transferase, malate dehydrogenase, and other structural and cytoskeletal proteins (i.e., actin, troponin T). Findings from this study are pivotal in updating the current knowledge on anthelmintic resistance and providing new insights into the defence mechanisms of resistant nematodes towards drug treatment.

Detection of Schistosoma spindale ova and associated risk factors among Malaysian cattle through coprological survey.

The present study was conducted to determine the occurrence of Schistosoma spindale ova and its associated risk factors in Malaysian cattle through a coprological survey. A total of 266 rectal fecal samples were collected from six farms in Peninsular Malaysia. The overall infection rate of S. spindale was 6% (16 of 266). Schistosoma spindale infection was observed in two farms, with a prevalence of 5.4% and 51.9%, respectively. This trematode was more likely to co-occur with other gastro-intestinal parasites (i.e., Dicrocoelium spp., Paramphistomum spp., strongyle, Eimeria spp. and Entamoeba spp.). Chi-square analysis revealed that female cattle are less likely to get S. spindale infection as compared to male cattle (OR = 0.3; 95% CI = 0.08-1.06; p < 0.05), and cattle weighing lower than 200 kg, were significantly at higher risk than those higher than 200 kg (OR = 5; 95% CI = 1.07-24.79; p < 0.05) to the infection. Multivariate analysis confirmed that among the cattle in Malaysia, the age (cattle with two year old and higher: OR = 21; 95% CI = 2.48-179.44; p < 0.05) and weight (weighing 200 kg and lower: OR = 17; 95% CI = 3.38-87.19; p < 0.05) were risk factors for S. spindale infection among Malaysian cattle.

First report of Rickettsia asembonensis in small ruminants.

Rickettsioses is a group of emerging infectious diseases in Southeast Asia caused by Gram-negative obligate intracellular bacteria in the Rickettsiae tribe. However, there is limited information regarding the vertebrate hosts of Rickettsia spp. in this region. This study aims to detect and identify Rickettsia agents present in wildlife and domesticated animals in Malaysia using Polymerase Chain Reaction (PCR) and sequencing of citrate synthase gene (gltA), followed by genotyping and phylogenetic analysis. Rickettsia sp. was detected in 2 (0.67%) of 300 wildlife and domesticated animal blood samples. The positive samples were derived from a goat (5.56% of 18) and a sheep (2.22% of 45). Both sequences demonstrated 99.64% sequence similarity to Rickettsia asembonensis, a species that is known to infect humans and macaques. This study reported for the first time the detection of R. asembonensis in sheep and goats in Malaysian farms, suggesting this species may be adapting to a wider range of animals, specifically farm animals. Therefore, this bacterium may pose a zoonotic threat to the local community particularly to the farmworkers or animal handlers. The low infection rate of this pathogen across different animals highlighted the need of continuous surveillance of emerging and reemerging pathogens among animal populations.

High lipid storage in vacoular forms of subtype 6 Blastocystis sp. in ostrich.

BACKGROUND: Blastocystis sp., a widely prevalent intestinal protozoan parasite is found in a wide range of animals, including humans. The possibility of zoonotic transmission to human from birds especially ostriches led us to investigate on the cross infectivity of Blastocystis sp. isolated from the ostrich feces as well as the phenotypic and subtype characteristics. There is a need to investigate this especially with the rising number of ostrich farms due to the growing global ostrich industry. FINDINGS: 100% of the ostriches were found to be positive for Blastocystis sp. using the in-vitro cultivation method. Transmission electron microscopy revealed high electron dense material in the central body of the vacoular forms. The membrane layer of the ostrich isolate was significantly (p = 0.003) thicker as compared to human isolate. Sudan staining revealed that this was lipid accumulation. We provide evidence for the first time, the existence of subtype 6 which has been previously reported only in pigs and cattle. Cysts, ranging from 3.0 to 7.0 µm in diameter caused experimental infection in Sprague Dawley rats implicating that Blastocystis sp. isolated from ostriches exhibits low host specificity. CONCLUSION: The study for the first time demonstrates that Blastocystis sp. subtype 6 do exist in ostriches and show high lipid storage in the vacuoles of the parasites. The study further provides evidence for potential zoonotic transmission in ostrich farms as Blastocystis subtype 6 can infect rats and the same subtype have been previously reported in humans.

Use of COI, CytB and ND5 genes for intra- and inter-specific differentiation of Haematobia irritans and Haematobia exigua.

A multilocus sequence analysis using mitochondria-encoded cytochrome c oxidase subunit I (COI), cytochrome B (CytB), NADH dehydrogenase subunit 5 (ND5); nuclear encoded 18S ribosomal RNA (18S) and 28S ribosomal RNA (28S) genes was performed to determine the levels of genetic variation between the closely related species Haematobia irritans Linnaeus and Haematobia exigua de Meijere. Among these five genes, ND5 and CytB genes were found to be more variable and informative in resolving the interspecific relationships of both species. In contrast, the COI gene was more valuable in inferring the intraspecific relationships. The ribosomal 18S and 28S sequences of H. irritans and H. exigua were highly conserved with limited intra- and inter-specific variation. Molecular evidence presented in this study demonstrated that both flies are genetically distinct and could be differentiated based on sequence analysis of mitochondrial genes.