A Major Trichinellosis Outbreak Suggesting a High Endemicity of Trichinella Infection in Northern Laos

Abstract

Trichinellosis is an important and under-recognized food-borne zoonosis in Southeast Asia. After 30 years of no reports, a small outbreak was described in Central Lao PDR (Laos) in 2003. Here we report a large outbreak of at least 650 estimated patients in Udomxay (northern Laos) in June 2005. Trichinella ELISA assays on serum from 133 patients and Western blot assays on 16 patients were positive in 67.6% and 81.2%, respectively. No deaths were recorded. Consumption of uncooked or fermented pork at funeral and wedding ceremonies was the main source of infection. Larvae of Trichinella spiralis were found in 1 of 11 local pigs not involved in this outbreak. The results suggest that trichinellosis may be an under-recognized but important endemic disease in Laos and reinforces the need to urgently implement veterinary and educational programs.

Trichinellosis in Vietnam

“…3 The identification of Trichinella larvae isolated from human biopsies and pigs from the 2012 outbreak as T. spiralis is in agreement with literature data that show that this species is the most widespread species infecting domestic pigs in southeast Asia, China, and most of the other world regions. 4,8,24,[33][34][35] The identification of the etiological agent as T. spiralis is also in agreement with the severity of the clinical picture, which resulted in the death of eight patients in the course of three of five outbreaks.…”

“…4,23,24 In the course of the last 50 years, there was an active animal black market between the borders of these countries, which favored the spread of Trichinella-infected pigs in the area. In Vietnam, excluding the outbreak of trichinellosis in the Saigon area caused by the consumption of pork from a wild boar, 11,12 Trichinella infections were documented only in domestic pigs and humans of the north Vietnamese provinces.…”

“…7 In Lao People's Democratic Republic, most of the patients were in the range of 28-33 years of age, and only 17 (12.3%) patient were in the pediatric age. 4 At the world level, trichinellosis affected primarily adults (median age = 33.1 years) and about equally affected men (51%) and women. 3 The identification of Trichinella larvae isolated from human biopsies and pigs from the 2012 outbreak as T. spiralis is in agreement with literature data that show that this species is the most widespread species infecting domestic pigs in southeast Asia, China, and most of the other world regions.…”

“…2 These zoonotic parasites have been detected in most southeast Asian countries (Lao People's Democratic Republic, Malaysia, Thailand, and Vietnam), but the recorded data are fragmentary. 2,[4][5][6][7][8][9] In Vietnam, Trichinella sp. was detected for the first time in 1923 in two (0.04%) of 4,952 pigs tested in Hanoi.…”

The Present Situation of Trichinellosis in Indochina (2001–2011)

“…In the database PubMed, there are two official reports on big outbreaks of trichinellosis in Laos and all has just been reported within this decade [9 -10]. Barennes et al concluded that "trichinellosis may be an under-recognized but important endemic disease in Laos and reinforces the need to urgently implement veterinary and educational programs [10]." Nevertheless, it is believed that the problem is still required management in this country.…”