Varicella zoster and fever rash surveillance in Lao People's Democratic Republic.

Background: In Lao PDR, the epidemiology of varicella infection is uncertain, since it is not a notifiable disease and VZV outbreaks are rarely reported as fever/rash (F/R) diseases.

Methods: We estimated the seroprevalence of VZV (IgG ELISA) in different age cohorts (9 months to 46 years; N = 3139) and investigated VZV and 6 other viruses in patients during F/R outbreaks and in an ad hoc sentinel site in the context of the national reporting system (IgM ELISA, PCR).

Results: At least 80% of the sampled population had evidence of VZV infection before the age of 15.

Chikungunya virus emergence in the Lao PDR, 2012-2013.

In May 2012, the first authenticated cases of active chikungunya virus infection were detected in Champasak Province, Southern Laos. Analysis of series of human samples and mosquito specimens collected during the outbreak and over the year that followed the emergence enabled the drawing up of a map of the progression of CHIKV and the establishment of a full genetic characterization of the virus.

The Lao Experience in Deploying Influenza A(H1N1)pdm09 Vaccine: Lessons Made Relevant in Preparing for Present Day Pandemic Threats.

The Lao PDR, as did most countries of the Mekong Region, embarked on a pandemic vaccine initiative to counter the threat posed by influenza A(H1N1)pdm09. Overall, estimated vaccine coverage of the Lao population was 14%, with uptake in targeted health care workers and pregnant women 99% and 41%, respectively. Adverse Events Following Immunization accounted for only 6% of survey driven, reported vaccination experiences, with no severe consequences or deaths.

Influenza seasonality and vaccination timing in tropical and subtropical areas of southern and south-eastern Asia.

Objective: To characterize influenza seasonality and identify the best time of the year for vaccination against influenza in tropical and subtropical countries of southern and south-eastern Asia that lie north of the equator.

Methods: Weekly influenza surveillance data for 2006 to 2011 were obtained from Bangladesh, Cambodia, India, Indonesia, the Lao People's Democratic Republic, Malaysia, the Philippines, Singapore, Thailand and Viet Nam. Weekly rates of influenza activity were based on the percentage of all nasopharyngeal samples collected during the year that tested positive for influenza virus or viral nucleic acid on any given week.

Causes of non-malarial fever in Laos: a prospective study.

Background: Because of reductions in the incidence of Plasmodium falciparum malaria in Laos, identification of the causes of fever in people without malaria, and discussion of the best empirical treatment options, are urgently needed. We aimed to identify the causes of non-malarial acute fever in patients in rural Laos.

Methods: For this prospective study, we recruited 1938 febrile patients, between May, 2008, and December, 2010, at Luang Namtha provincial hospital in northwest Laos (n=1390), and between September, 2008, and December, 2010, at Salavan provincial hospital in southern Laos (n=548).

National dengue surveillance in the Lao People's Democratic Republic, 2006-2012: epidemiological and laboratory findings.

Although dengue has been a public health problem for several decades in the Lao People's Democratic Republic, the magnitude of the disease burden and epidemiological trends remain poorly understood. We analysed national dengue surveillance and laboratory data from 2006 to 2012 by person, place and time. Between 2006 and 2012, the annual dengue notification rate ranged between 62 and 367 cases per 100 000 population with an apparent geographical expansion of transmission throughout the country in recent years and concurrent co-circulation of all four dengue virus subtypes.

Chronic hepatitis B prevalence among children and mothers: results from a nationwide, population-based survey in Lao People's Democratic Republic.

Background: Hepatitis B is regarded as a serious public health issue in Lao People's Democratic Republic (Lao PDR), a Southeast Asian country. However, disease epidemiology among the general population is not well known, and thus a nationwide cross-sectional survey for hepatitis B surface antigen (HBsAg) prevalence in children and their mothers was conducted.

Methods And Findings: We applied three-stage cluster sampling using probability proportionate to size.

Emergence of chikungunya in Moonlapamok and Khong Districts, Champassak Province,the Lao People's Democratic Republic, May to September 2012.

Introduction: Chikungunya is a vector-borne disease transmitted to humans by Aedes mosquitoes, which are widespread in the Lao People's Democratic Republic. However, chikungunya virus (CHIKV) had not been detected in the country before outbreaks reported in July 2012. The first outbreaks were detected through health care worker event-based surveillance.

Respiratory virus infections in hospitalized children and adults in Lao PDR.

Background: Acute respiratory infections are an important cause of morbidity and mortality worldwide, with a major burden of disease in developing countries. The relative contribution of viruses in acute lower respiratory infections (ALRI) is, however, poorly documented in Lao PDR.

Objective: The objective of this study is to investigate the etiology of ALRI in patients of all ages in two hospitals of Laos.

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.

An early report from newly established laboratory-based influenza surveillance in Lao PDR.

Background: Prior to 2007, little information was available about the burden of influenza in Laos. We report data from the first laboratory-based influenza surveillance system established in the Lao People's Democratic Republic.

Methods: Three hospitals in the capital city of Vientiane began surveillance for influenza-like illness (ILI) in outpatients in 2007 and expanded to include hospitalized pneumonia patients in 2008.