First human infection of avian influenza A(H5N6) virus reported in Lao People's Democratic Republic, February-March 2021.

In March 2021, Lao People's Democratic Republic (Laos) reported an avian influenza A(H5N6) virus infection in a 5-year-old child identified through sentinel surveillance. This was the first human A(H5N6) infection reported outside of China. A multidisciplinary investigation undertook contact tracing and enhanced human and animal surveillance in surrounding villages and live bird markets.

Estimating the national burden of hospitalizations for influenza-associated severe acute respiratory infection in the Lao People's Democratic Republic, 2016.

Objective: Estimates of the burden of influenza are needed to inform prevention and control activities for seasonal influenza, including to support the development of appropriate vaccination policies. We used sentinel surveillance data on severe acute respiratory infection (SARI) to estimate the burden of influenza-associated hospitalizations in the Lao People's Democratic Republic.

Methods: Using methods developed by the World Health Organization, we combined data from hospital logbook reviews with epidemiological and virological data from influenza surveillance from 1 January to 31 December 2016 in defined catchment areas for two sentinel sites (Champasack and Luang Prabang provincial hospitals) to derive population-based estimates of influenza-associated SARI hospitalization rates.

National burden of influenza-associated hospitalizations in Cambodia, 2015 and 2016.

Introduction: The burden of influenza in Cambodia is not well known, but it would be useful for understanding the impact of seasonal epidemics and pandemics and to design appropriate policies for influenza prevention and control. The severe acute respiratory infection (SARI) surveillance system in Cambodia was used to estimate the national burden of SARI hospitalizations in Cambodia.

Methods: We estimated age-specific influenza-associated SARI hospitalization rates in three sentinel sites in Svay Rieng, Siem Reap and Kampong Cham provinces.

How elimination of lymphatic filariasis as a public health problem in the Kingdom of Cambodia was achieved.

Background: Endemicity of lymphatic filariasis (LF) in Cambodia was proven in 1956 when microfilariae were detected in mosquitos in the Kratié province. In 2001, an extensive study confirmed the presence of both Brugia malayi and Wuchereria bancrofti microfilariae. In 2003, the Ministry of Health established a national task force to develop policies and strategies for controlling and eliminating neglected tropical diseases (NTDs), with the goal of eliminating LF by 2015.

Using a hospital admission survey to estimate the burden of influenza-associated severe acute respiratory infection in one province of Cambodia-methods used and lessons learned.

Background: Understanding the burden of influenza-associated severe acute respiratory infection (SARI) is important for setting national influenza surveillance and vaccine priorities. Estimating influenza-associated SARI rates requires hospital-based surveillance data and a population-based denominator, which can be challenging to determine.

Objectives: We present an application of the World Health Organization's recently developed manual (WHO Manual) including hospital admission survey (HAS) methods for estimating the burden of influenza-associated SARI, with lessons learned to help others calculate similar estimates.

Establishing seasonal and alert influenza thresholds in Cambodia using the WHO method: implications for effective utilization of influenza surveillance in the tropics and subtropics.

Objective: To establish seasonal and alert thresholds and transmission intensity categories for influenza to provide timely triggers for preventive measures or upscaling control measures in Cambodia.

Methods: Using Cambodia's influenza-like illness (ILI) and laboratory-confirmed influenza surveillance data from 2009 to 2015, three parameters were assessed to monitor influenza activity: the proportion of ILI patients among all outpatients, proportion of ILI samples positive for influenza and the product of the two. With these parameters, four threshold levels (seasonal, moderate, high and alert) were established and transmission intensity was categorized based on a World Health Organization alignment method.

Seroprevalence and Transmission of Human Influenza A(H5N1) Virus before and after Virus Reassortment, Cambodia, 2006-2014.

Thirty-five human influenza A(H5N1) cases were reported in Cambodia during 2013-2014 after emergence of a clade 1.1.2 reassortant virus.

Introducing seasonal influenza vaccine in low-income countries: an adverse events following immunization survey in the Lao People's Democratic Republic.

Objective: In 2012, Lao PDR introduced seasonal influenza vaccine in pregnant women, persons aged ≥50 years, persons with chronic diseases, and healthcare personnel. We assessed adverse events following immunization (AEFI).

Methods: We used a multistage randomized cluster sample design to interview vaccine recipients.

Identification of molecular markers associated with alteration of receptor-binding specificity in a novel genotype of highly pathogenic avian influenza A(H5N1) viruses detected in Cambodia in 2013.

Human infections with influenza A(H5N1) virus in Cambodia increased sharply during 2013. Molecular characterization of viruses detected in clinical specimens from human cases revealed the presence of mutations associated with the alteration of receptor-binding specificity (K189R, Q222L) and respiratory droplet transmission in ferrets (N220K with Q222L). Discovery of quasispecies at position 222 (Q/L), in addition to the absence of the mutations in poultry/environmental samples, suggested that the mutations occurred during human infection and did not transmit further.

Assessment of gender distribution in dengue surveillance data, the Lao People's Democratic Republic.

Objective: Adolescent and young adult males account for a large proportion of dengue cases reported through national surveillance systems in the Western Pacific Region. To preliminarily assess the validity of these observed distributions, a field investigation was conducted in the Lao People's Democratic Republic's Savannakhet Province in November 2011.

Methods: Mixed quantitative and qualitative methods were used.

Capacity building in response to pandemic influenza threats: Lao PDR case study.

The Lao People's Democratic Republic (PDR) committed to pandemic detection and response preparations when faced with the threat of avian influenza. Since 2006, the National Center for Laboratory and Epidemiology of Lao PDR has developed credible laboratory, surveillance, and epidemiological (human) capacity and as a result was designated a World Health Organization National Influenza Center in 2010. The Lao PDR experience in building influenza capacities provides a case study of the considerable crossover effect of such investments to augment the capacity to combat emerging and re-emerging diseases other than influenza.

Epidemiological and virological characteristics of seasonal and pandemic influenza in Lao PDR, 2008-2010.

Background: Information on influenza virology and epidemiology from Lao PDR is limited and the seasonal patterns of influenza have not been previously described.

Objectives: To describe epidemiological and virologic characteristics of influenza in Lao PDR to recommend public health interventions, including improvements in surveillance and response.

Patients/methods: We performed a descriptive analysis of samples taken from patients with influenza-like-illness (ILI) (fever >38°C with cough and/or sore throat) presenting at seven sentinel hospitals in three regions of Lao PDR, January 2008-December 2010.

Molecular subtyping in cholera outbreak, Laos, 2010.

A cholera outbreak in Laos in July 2010 involved 237 cases, including 4 deaths. Molecular subtyping indicated relatedness between the Vibrio cholerae isolates in this and in a 2007 outbreak, uncovering a clonal group of V. cholerae circulating in the Mekong basin.

A cholera epidemic in Sekong Province, Lao People's Democratic Republic, December 2007-January 2008.

Recent large-scale outbreaks in the Lao People's Democratic Republic (Lao PDR) were reported in 1993 and 1994 and from 2000 to 2002. On December 23, 2007, a drastic increase in acute watery diarrhea patients at a health center in Sekong Province was reported to the provincial health office. An outbreak investigation was initiated to understand the magnitude of the outbreak, identify new cases, identify the suspected causal agent, implement control measures, and prevent new cases.

Low-technology cooling box for storage of malaria RDTs and other medical supplies in remote areas.

Background: With the increase in use of point-of-care diagnostic tests for malaria and other diseases comes the necessity of storing the diagnostic kits and the drugs required for subsequent management, in remote areas, where temperatures are high and electricity supply is unreliable or unavailable.

Methods: To address the lack of temperature-controlled storage during the introduction of community-based malaria management in Cambodia, the Cambodian National Centre for Parasitology, Entomology and Malaria Control (CNM) developed prototype evaporative cooling boxes (Cambodian Cooler Boxes - CCBs) for storage of perishable medical commodities in remote clinics. The performance of these CCBs for maintaining suitable storage temperatures was evaluated over two phases in 2005 and 2006-7, comparing conditions in CCBs using water as designed, CCBs with no water for evaporation, and ambient storage room temperatures.

Large-scale preventive chemotherapy for the control of helminth infection in Western Pacific countries: six years later.

In 2001, Urbani and Palmer published a review of the epidemiological situation of helminthiases in the countries of the Western Pacific Region of the World Health Organization indicating the control needs in the region. Six years after this inspiring article, large-scale preventive chemotherapy for the control of helminthiasis has scaled up dramatically in the region. This paper analyzes the most recent published and unpublished country information on large-scale preventive chemotherapy and summarizes the progress made since 2000.

Pfmdr1 and in vivo resistance to artesunate-mefloquine in falciparum malaria on the Cambodian-Thai border.

Artemisinin combination therapies (ACTs) have recently been adopted as first-line therapy for Plasmodium falciparum infections in most malaria-endemic countries. In this study, we estimated the association between artesunate-mefloquine therapy failure and genetic changes in the putative transporter, pfmdr1. Blood samples were acquired from 80 patients enrolled in an 2004 in vivo efficacy study in Pailin, Cambodia, and genotyped for pfmdr1 copy number and haplotype.

Efficacy of artemether-lumefantrine for the treatment of uncomplicated falciparum malaria in northwest Cambodia.

Objective: To determine the efficacy of artemether-lumefantrine malaria treatment, as an alternative to artesunate + mefloquine, which is becoming ineffective in some areas of the Thai-Cambodian border.

Methods: Two studies were conducted to monitor the efficacy of artemether-lumefantrine in Sampov Lun referral hospital, Battambang Province, in 2002 and 2003, and one study was conducted to assess the efficacy of mefloquine + artesunate in 2003 for comparison. The studies were performed according to the WHO standardized protocol with a follow-up of 28 days.

Surveillance of the efficacy of artesunate and mefloquine combination for the treatment of uncomplicated falciparum malaria in Cambodia.

Artesunate and mefloquine combination treatment has been used since 2000 in Cambodia as the first-line drug for the treatment of uncomplicated falciparum malaria. In order to assess its efficacy and safety, the national malaria control programme conducted 14 therapeutic efficacy studies with the drug combination between 2001 and 2004 at nine sites. In 2001 and 2002, co-blister packs of artesunate and mefloquine were used, whereas in 2003 and 2004, drugs were given individually from a bulk pack at a total dose of 12 mg/kg of artesunate and 25 mg/kg of mefloquine over 3 days.

Malaria rapid diagnostic tests in tropical climates: the need for a cool chain.

Malaria control programs in endemic countries increasingly rely on early case detection and treatment at village level. The rapid diagnostic tests (RDTs) and accompanying drugs on which the success of these programs depends deteriorate to varying degrees at high temperatures. To assess the ability of health systems to maintain RDTs within manufacturers' specifications, we monitored temperatures in the delivery chain from manufacturer through to the village health worker in Cambodia and the Philippines.

Financial costs of deworming children in all primary schools in Cambodia.

In 2002, Cambodia's Ministry of Health launched a deworming programme to deliver an anthelmintic drug (mebendazole 500 mg) and health education to 75% of its school children twice a year. Cambodia's school population is approximately 2.8 million.

Mekong malaria. II. Update of malaria, multi-drug resistance and economic development in the Mekong region of Southeast Asia.

In an expansion of the first Mekong Malaria monograph published in 1999, this second monograph updates the malaria database in the countries comprising the Mekong region of Southeast Asia. The update adds another 3 years' information to cover cumulative data from the 6 Mekong countries (Cambodia, China/Yunnan, Lao PDR, Myanmar, Thailand, Viet Nam) for the six-year period 1999-2001. The objective is to generate a more comprehensive regional perspective in what is a global epicenter of drug resistant falciparum malaria, in order to improve malaria control on a regional basis in the context of social and economic change.

In vitro monitoring of Plasmodium falciparum susceptibility to artesunate, mefloquine, quinine and chloroquine in Cambodia: 2001-2002.

We used a classical isotopic microtest to assess the in vitro sensitivity of 352 Plasmodium falciparum isolates collected in Cambodia in 2001 and 2002 to chloroquine, mefloquine, quinine and artesunate. Our results confirm conclusions drawn from earlier studies conducted by the Cambodian national malaria centre. Chloroquine-resistant phenotypes were highly prevalent in Cambodia.