Assessment of the anthelmintic efficacy of albendazole in school children in seven countries where soil-transmitted helminths are endemic.

BACKGROUND: The three major soil-transmitted helminths (STH) Ascaris lumbricoides, Trichuris trichiura and Necator americanus/Ancylostoma duodenale are among the most widespread parasites worldwide. Despite the global expansion of preventive anthelmintic treatment, standard operating procedures to monitor anthelmintic drug efficacy are lacking. The objective of this study, therefore, was to define the efficacy of a single 400 milligram dose of albendazole (ALB) against these three STH using a standardized protocol. METHODOLOGY/PRINCIPAL FINDINGS: Seven trials were undertaken among school children in Brazil, Cameroon, Cambodia, Ethiopia, India, Tanzania and Vietnam. Efficacy was assessed by the Cure Rate (CR) and the Fecal Egg Count Reduction (FECR) using the McMaster egg counting technique to determine fecal egg counts (FEC). Overall, the highest CRs were observed for A. lumbricoides (98.2%) followed by hookworms (87.8%) and T. trichiura (46.6%). There was considerable variation in the CR for the three parasites across trials (country), by age or the pre-intervention FEC (pre-treatment). The latter is probably the most important as it had a considerable effect on the CR of all three STH. Therapeutic efficacies, as reflected by the FECRs, were very high for A. lumbricoides (99.5%) and hookworms (94.8%) but significantly lower for T. trichiura (50.8%), and were affected to different extents among the 3 species by the pre-intervention FEC counts and trial (country), but not by sex or age. CONCLUSIONS/SIGNIFICANCE: Our findings suggest that a FECR (based on arithmetic means) of >95% for A. lumbricoides and >90% for hookworms should be the expected minimum in all future surveys, and that therapeutic efficacy below this level following a single dose of ALB should be viewed with concern in light of potential drug resistance. A standard threshold for efficacy against T. trichiura has yet to be established, as a single-dose of ALB is unlikely to be satisfactory for this parasite. TRIAL REGISTRATION: ClinicalTrials.gov NCT01087099.

A human case of subcutaneous dirofilariasis caused by Dirofilaria repens in Vietnam: histologic and molecular confirmation.

Human dirofilariasis caused by infection with Dirofilaria worms has been frequently reported. The symptoms associated with infection by these filarial parasites, which are transmitted to humans by zooanthropophilic mosquitoes, are characterized by mainly pulmonary and subcutaneous nodules. Here, we report the first case in Vietnam of a subcutaneous dirofilariasis with a painful nodule in the right eyelid. An immature female worm was removed by excisional biopsy and identified as Dirofilaria repens by histology and DNA analysis.

Acute febrile myalgia in Vietnam due to trichinellosis following the consumption of raw pork.

Trichinellosis outbreaks occur occasionally in Vietnam following the consumption of undercooked pork. Diagnosing trichinella can be problematic because fever and myalgia are nonspecific, and diagnosis may be delayed. We describe 5 Vietnamese patients in whom trichinellosis was diagnosed after several weeks of illness.

High latrine coverage is not reducing the prevalence of soil-transmitted helminthiasis in Hoa Binh province, Vietnam.

A baseline epidemiological survey for parasite infections was conducted between December 2007 and January 2008 in 155 villagers in a rural commune in Hoa Binh province, Vietnam. The prevalence of Ascaris lumbricoides, Trichuris trichiura and hookworm infection was 13.5%, 45.2% and 58.1%, respectively. At least one of the parasites was detected in 72.3% of the samples. We found no association between infection with A. lumbricoides or T. trichiura and engagement in agriculture, while hookworm infection was more prevalent in populations having frequent contact with soil. Agricultural use of human faeces was not correlated with any of the infections. We suggest that the consumption of vegetables that are commonly fertilized with human faeces in the community has led to the high infection rates with A. lumbricoides and T. trichiura, rather than the manipulation of faeces in farming activity. This also explains the high infection prevalence, despite high latrine coverage (98.1%) in the study population. The presence of latrines alone is not sufficient to reduce the prevalence of helminthiasis in a rural agricultural community if fresh faeces are used as fertilizer.

Prevalence, intensity and risk factors for clonorchiasis and possible use of questionnaires to detect individuals at risk in northern Vietnam.

A high prevalence of the liver flukes Clonorchis sinensis and Opisthorchis viverrini has been reported in a number of provinces in Vietnam. Knowledge about C. sinensis infection gained from Thailand over the past decade suggests that the habit of eating raw freshwater fish is a major risk factor for infection. However, further information to confirm this is needed. In the present study 1155 villagers in two communes in northern Vietnam were interviewed and their stools were examined for the presence of liver flukes. The prevalence of infection was 26% and was 3.6 times higher in males than in females. The habit of eating raw fish increased the risk of C. sinensis infection 53-fold. These results provide evidence of a strong correlation between the intensity of C. sinensis infection and the cumulative quantity of freshwater fish consumed in a lifetime and suggest that simple questionnaires could be used in endemic areas to quickly identify populations at risk and enable targeted treatment.