Genomic epidemiology of SARS-CoV-2 in Cambodia, January 2020 to February 2021.

The first case of coronavirus disease 2019 (COVID-19) in Cambodia was confirmed on 27 January 2020 in a traveller from Wuhan. Cambodia subsequently implemented strict travel restrictions, and although intermittent cases were reported during the first year of the COVID-19 pandemic, no apparent widespread community transmission was detected. Investigating the routes of severe acute respiratory coronavirus 2 (SARS-CoV-2) introduction into the country was critical for evaluating the implementation of public health interventions and assessing the effectiveness of social control measures. Genomic sequencing technologies have enabled rapid detection and monitoring of emerging variants of SARS-CoV-2. Here, we detected 478 confirmed COVID-19 cases in Cambodia between 27 January 2020 and 14 February 2021, 81.3 per cent in imported cases. Among them, fifty-four SARS-CoV-2 genomes were sequenced and analysed along with representative global lineages. Despite the low number of confirmed cases, we found a high diversity of Cambodian viruses that belonged to at least seventeen distinct PANGO lineages. Phylogenetic inference of SARS-CoV-2 revealed that the genetic diversity of Cambodian viruses resulted from multiple independent introductions from diverse regions, predominantly, Eastern Asia, Europe, and Southeast Asia. Most cases were quickly isolated, limiting community spread, although there was an A.23.1 variant cluster in Phnom Penh in November 2020 that resulted in a small-scale local transmission. The overall low incidence of COVID-19 infections suggests that Cambodia's early containment strategies, including travel restrictions, aggressive testing and strict quarantine measures, were effective in preventing large community outbreaks of COVID-19.

Human Outbreak of Trichinellosis Caused by Trichinella papuae Nematodes, Central Kampong Thom Province, Cambodia.

In September 2017, a severe trichinellosis outbreak occurred in Cambodia after persons consumed raw wild pig meat; 33 persons were infected and 8 died. We collected and analyzed the medical records for 25 patients. Clinical signs and symptoms included myalgia, facial or peripheral edema, asthenia, and fever. We observed increased levels of creatine phosphokinase and aspartate aminotransferase-, as well as eosinophilia. Histopathologic examination of muscle biopsy specimens showed nonencapsulated Trichinella larvae. A Trichinella excretory/secretory antigen ELISA identified Trichinella IgM and IgG. Biopsy samples were digested and larvae were isolated and counted. PCR for the 5S rDNA intergenic spacer region and a multiplex PCR, followed by sequencing identified the parasite as Trichinella papuae. This species was identified in Papua New Guinea during 1999 and in several outbreaks in humans in Thailand. Thus, we identified T. papuae nematodes in humans in Cambodia.

Rapid metagenomic characterization of a case of imported COVID-19 in Cambodia.

Rapid production and publication of pathogen genome sequences during emerging disease outbreaks provide crucial public health information. In resource-limited settings, especially near an outbreak epicenter, conventional deep sequencing or bioinformatics are often challenging. Here we successfully used metagenomic next generation sequencing on an iSeq100 Illumina platform paired with an open-source bioinformatics pipeline to quickly characterize Cambodia's first case of COVID-2019.

Outbreak detection of influenza-like illness in Prey Veng Province, Cambodia: a community-based surveillance.

On June 4, 2016, the Prey Veng Provincial Health Department reported a total of 107 patients with influenza-like illness (ILI) from Chakhlanh village to the Cambodian Ministry of Health. To confirm the outbreak and evaluate its clinical and epidemiological characteristics, the investigation team visited the village and reviewed the case-based surveillance (CBS) data on severe respiratory infection (SRI) and patients' records in health facilities. The team interviewed all households in the village from May 1 to June 5, 2016 and obtained the following data: age, medical history, date of onset, treatment, symptoms, and history of contact with patients or dead poultry. Nasal swab samples were collected from suspected ILI cases to test for influenza virus by RT-PCR. The investigation detected 498 suspected ILI cases, including 288 females. Although the incidence of suspected ILI cases who visited health centers was 63.0 per 1,000 persons per month, the attack rate was 27.1 per 100 population. The major age group was 5-14 years followed by 0-4 years. Major symptoms were cough, fever, runny nose, and headache. Six of seven nasal swab samples were positive for influenza A/H1N1 pdm09 virus. Most children with flu symptoms had contact with previous cases. This study showed that the ILI outbreak might be caused by seasonal influenza A/H1N1 pdm09 spread from person to person. Poor living conditions and poor hygiene and sanitation practices were environmental factors that caused the outbreak. As the CBS system was unable to identify this epidemic, it needs to be improved.