Patterns of trematode infections of Opisthorchis viverrini (Opisthorchiidae) and Haplorchis taichui (Heterophyidae) in human populations from two villages in Savannakhet Province, Lao PDR.

The liver fluke, Opisthorchis viverrini, and the minute intestinal fluke, Haplorchis taichui, are prevalent in many Asian countries. This study analysed the patterns of infections of O. viverrini and H. taichui in Lahanam and Thakhamlien villages (Savannakhet Province, Lao PDR), in two cross-sectional investigations. Out of a total of 207 human participants, post-anthelmintic treatment positivity rates for expelled worms were 170 (82.1%) for H. taichui and 65 (31.4%) for O. viverrini. Both these species co-exist in the study villages. When each parasite was analysed separately, H. taichui infections reached a plateau among people aged >20 years. Opisthorchis viverrini infection rates were highest in the age group 21-30 years, with decreasing infection rates after the age of 30. Our findings indicated that fish-borne trematode infections were more prevalent among adults. Fish, common intermediate hosts, were acquired in the study area for analysis. The examination of 35 species of fish as intermediate hosts found O. viverrini metacercariae in only six species, and these were found mostly during the month of November. Many farmers who live on the rice fields obtain their food from their immediate environment, including these intermediate-host fish, potentially putting them at greater risk of O. viverrini infection. By contrast, H. taichui metacercariae were found in three species of fish obtained from the market, meaning that anyone could consume them and become infected. If people who work in rice fields limit the species of fish they consume, or avoid consuming raw fish during the month of November, they may reduce their risk of O. viverrini infection.

An open, randomized comparison of artesunate plus mefloquine vs. dihydroartemisinin-piperaquine for the treatment of uncomplicated Plasmodium falciparum malaria in the Lao People's Democratic Republic (Laos).

OBJECTIVE: To determine the efficacy and safety of oral dihydroartemisinin-piperaquine (DP, Artekin) in the treatment of uncomplicated Plasmodium falciparum malaria in southern Laos. METHODS: An open, randomized clinical trial of oral artesunate-mefloquine (AM) vs. DP in 220 patients with acute uncomplicated falciparum malaria in Savannakhet Province, Laos. RESULTS: The 42-day cure rates (95% CI), as determined by survival analysis and adjusted for reinfection, were excellent and similar for the two groups [99 (94-100)% and 100 (100-100)% for AM and DP, respectively]. The median (range) fever and parasite clearance times for the AM and DP groups were also similar [20 (4-63) h and 2 (1-4) days vs. 20 (7-57) and 2 (1-4) days, logrank P = 0.4 and 0.17, respectively]. There were more patients with at least one potential side effect following treatment in the AM group when compared with the DP group [64/110 (58%) vs. 48/110 (44%), respectively, P = 0.031]. CONCLUSION: Dihydroartemisinin-piperaquine did not have superior efficacy to AM for the treatment of uncomplicated falciparum malaria in Laos but was associated with fewer adverse effects.

Clinical presentation of childhood malaria in Savannakhet province, Lao PDR.

A descriptive study on the clinical presentation of childhood malaria was conducted in Savannakhet Province, Lao People's Democratic Republic. It is aimed to describe the clinical features and to determine the association between the severity of malaria and the initiation or delay of treatment. A total number of 92 children 1-14 years of age with confirmed malaria diseases were enrolled in this study. Fifty-six cases (60.9%) had illness for less than 3 days before hospitalized and 36 cases (39.1%) for more than 3 days. Twenty-nine cases (31.5%) had self antimalarial medication before admission (9 cases of chloroquine, 16 cases of quinine and 4 cases of artesunate). Ten cases (10.9%) had abnormal consciousness of which 7 cases (7.6%) had confusion but responded to verbal command and 3 cases (3.3%) were in coma not respond to painful stimuli but had reflex. Two cases 2.2%) had convsulsions, 11 cases (12.0%) had dehydration, 47 cases (51.1%) had vomiting, 18 cases (19.6%) had hepatomegaly and 19 cases (20.7%) had splenomegaly. There was a statistically significant association between consciousness levels and the duration of illness before admission < or = 3 days and > 3 days (p = 0.01) while there is no significant difference between parasitemia density and the duration of illness before admission (p > 0.05).

Childhood malaria in the Lao People's Democratic Republic.

The idea that malaria in South-East Asia is synonymous with adult malaria is questioned in this paper. In the Lao People's Democratic Republic, community-based malariometric data were collected in Savannakhet Province, which shares borders with Viet Nam in the east and Thailand in the west. The data indicate that endemic malaria is rural and stable in large areas of the province. In these areas, which are rarely subject to malaria control, there is significant childhood malaria. A little more than one-quarter of individuals examined in mass blood surveys carried out in the peak malaria season were parasite-positive. Unlike other studies in the region reporting a declining risk of positive parasitaemia with age, thus suggesting immunity consistent with high and prolonged exposure to malaria, the communities studied in the Lao People's Democratic Republic did not show the expected acquisition of immunity. Further community-based studies on this matter are therefore warranted.