Dear Editor,
Environmental epidemiology surveillance is an important tool in environmental medicine and public health. Many infections disease are associated with contamination in environmental samples and the data from environmental surveillance are useful for public health planning for management of the problem (1). In clinical parasitology, contamination of parasite egg and metacercariae are possible and it might be related to disease outbreak.
In tropical countries, contamination in big city is also possible and the problem is usually neglected.
Here, the authors discuss on the situation from Indochina where opisthorchiasis is very common (2). For surveillance, environmental monitoring of metacercariae in intermediate host is regularly done. Malacological epidemiology of Opisthorchis spp. is an important public health parameter. Since 2020, the new emerging severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection also attack Indochina and this area is the second area after China that disease has existed since early January 2020 (3). Until present, the disease is still not successfully controlled. Disease surveillance is regularly done. Of several surveillance system, sewage viral epidemiology of SARS-CoV-2 is also important public health surveillance in this area (4).
In the same area that both parasitic disease and Coronavirus disease-2019 (COVID-19) are common, little data on environmental epidemiology are available. Here, the authors reappraise on available data from an area in Indochina that COVID-19 and opisthorchiasis are common problems.
The authors reanalyzed the most recent public available data in 2021 on malacological epidemiology of opisthorchis spp. and sewage viral epidemiology of SARS-CoV-2 in a city area (GPS location 13.76779525743989, 100.6687726131797) in Indochina (4,5). Based on primary data from the environmental metagenomics studies (4,5), primary data on location related prevalence of both Opisthorchis spp. Contamination in snails and SARS-CoV-2 contamination in waste water are collected and used for construct of overlapping GIS map as shown in Figure 1.
Regarding relationship, although there is no statistical association, there is a trend of co-occurrence of contamination of both Opisthorchis spp. in snails and SARS-CoV-2 in sewage samples in the same area. Since poor sanitation is the rooted cause of contamination of either parasite sor virus into environmental samples, hence, the environmental contamination detection should give the result in the same way. Detection of contamination by an infective agent might be an indirect clue for requirement for sanitation improvement for prevention for any other pathogens as well.
*Ethics
Peer-review: Internally peer-reviewed.
* Authorship Contributions
Surgical and Medical Practices: P.S., V.W., Concept: P.S., V.W., Design: P.S., V.W., Data Collection or Processing: P.S., V.W., Analysis or Interpretation: P.S., V.W., Literature Search: P.S., V.W., Writing: P.S., V.W.
Conflict of Interest: No conflict of interest was declared by the authors.
Financial Disclosure: The authors declared that this study received no financial support.
