Risk profiling and efficacy of albendazole against the hookworms Necator americanus and Ancylostoma ceylanicum in Cambodia to support control programs in Southeast Asia and the Western Pacific.

Background: Hookworm disease is endemic throughout many parts of the Asia Pacific, despite targeted control programs of at-risk populations. The success of these programs has been hindered by the limited efficacy of widely-used mebendazole, rapid re-infection rates linked to persistent reservoirs of untreated people and dogs, and the low sensitivity of conventional coprodiagnostic techniques employed. Methods: Here, we used standard faecal flotation (SFF) and a multiplex qPCR (mqPCR) assay to calculate and compare species-specific cure and egg reduction rates of single dose albendazole (400 mg) against hookworm infections at community level. Data from a cross-sectional survey in 1,232 people from Cambodia were used to inform a generalised linear mixed model to identify risk factors linked to hookworm infection(s) at baseline. Furthermore, we calculated risk factors associated to the probability of being cured after albendazole administration. Findings: Overall, 13·5% of all 1,232 people tested by SFF were positive for hookworm infection(s). Most (80·1%) infected people were >12 years of age, hence above the age targeted by the WHO control program. We estimate that as age increases, the odds of being infected increases at a faster rate for females than for males. We revealed a substantial difference in cure rate of hookworm infection(s) following albendazole treatment using the SFF (81·5%) and mqPCR (46·4%) assays, and provide the first data on the efficacy of this drug against the zoonotic hookworm Ancylostoma ceylanicum. We estimated that as age increases by one year, the odds of being cured decreases by 0·4%-3·7%. Similarly, the odds of being cured for people who boiled drinking water was estimated to be between 1·02 and 6·82. Interpretation: These findings show that the adoption of refined diagnostic techniques is central to monitoring hookworm infection(s) and the success of control strategies, which can ultimately aid in reducing associated morbidity in human populations. The approach taken is likely to be directly applicable to other parts of Southeast Asia and the Western Pacific, where specific epidemiological conditions might hamper the success of targeted treatment programs. Funding: Faculty of Veterinary and Agricultural Sciences Strategic Research Funds, The University of Melbourne.

Development and Evaluation of a Multiplex Quantitative Real-Time Polymerase Chain Reaction for Hookworm Species in Human Stool.

Hookworm disease caused by Necator americanus, Ancylostoma duodenale, and Ancylostoma ceylanicum affects half a billion people worldwide. The prevalence and intensity of infection of individual hookworm species are vital for assessing morbidity and generating targeted intervention programs for their control. The present study aims to evaluate a multiplex real-time quantitative PCR (qPCR) assay to determine the prevalence and egg intensity of all three hookworm species and compare this with standard microscopy and published genus-based conventional and real-time multiplex qPCRs. Performance of the diagnostic assays was evaluated using DNA extracted from 192 fecal samples collected as part of a soil-transmitted helminth (STH) survey in northern Cambodia. The prevalence of hookworms as detected by the multiplex hookworm qPCR of 84/192 (43.8%) was significantly higher than that using microscopy of 49/192 (25.5%). The hookworm multiplex qPCR showed very good agreement for the detection of both N. americanus (Kappa 0.943) and Ancylostoma spp. (Kappa 0.936) with a multiplex STH qPCR. A strong and moderate quantitative correlation between cycle threshold and eggs per gram (EPG) feces was obtained for the hookworm qPCR for seeded DNA egg extracts (R 2 ≥ 0.9004) and naturally egg-infected individuals (R 2 = 0.6848), respectively. The newly developed hookworm quantitative multiplex qPCR has the potential for application in anthelmintic efficacy trials and for monitoring the success of mass deworming programs targeting individual species of anthroponotic and zoonotic hookworms.

Hepatitis C virus in healthy blood donors in Sri Lanka.

INTRODUCTION: Hepatitis C virus (HCV) is the etiological agent for the majority of cases of non-A, non-B hepatitis. As a blood-borne virus, HCV is widely recognized as a major causative agent of post-transfusion non-A, non-B hepatitis. The prevalence of HCV and the distribution of HCV genotypes in Sri Lanka in comparison with the rest of Asia are not well known. MATERIALS AND METHODS: The blood samples collected from healthy blood donors at the National Blood Transfusion Centre of Sri Lanka were screened to determine the prevalence and the genotypes of HCV among blood donors in Sri Lanka. RESULTS: HCV antibodies were found in 53 of 4980 blood donors. However, of the 53 only 8 positive results were confirmed by Reverse Transcription-PCR, which suggests frequent false-positive results or viral clearance. The PCR positive samples were genotyped by DNA sequencing of the Core/E1 regions of HCV genome, and all the HCV viruses belonged to genotype 3, of which 7 were 3a and 1 was 3b. CONCLUSION: HCV is relatively rare among blood donors in Sri Lanka and only genotype 3 was detected in the studied group.

Genotypes of hepatitis C virus (HCV) in liver disease patients in Sri Lanka.

A total of 460 samples (serum or plasma) were obtained from clinically diagnosed liver disease patients from January 2006 to December 2007 and subjected to reverse transcription--polymerase chain reaction (RT-PCR) based detection of HCV. Of these, 32 samples (6.9%) were positive for HCV RNA. Samples that were positive for HCV were genotyped with type specific primers. The genotyping assay was validated by DNA sequencing and phylogenetic analysis. The Sri Lankan isolates were comprised predominantly of genotype 1b (46.9%) followed by genotype 2b (21.9%), 2a (15.6%) and mixed infection with genotypes 1b and 2b (3.1%). This is the first report of the distribution of HCV genotypes in Sri Lanka.