Skip to main content
  • Letter to the Editor
  • Open access
  • Published:

Trend of Entamoeba histolytica infestation in Kolkata

Abstract

Background

Entamoeba histolytica infection is found almost all over the world and is highly endemic and a major cause of parasitic diarrhoea particularly in the developing countries.

Methods

A systemic surveillance was set up at the Infectious Disease hospital, Kolkata, India between November 2007 and October 2009 for understanding the trend of E. histolytica infection in Kolkata. Fecal samples were collected from diarrhoeal patients attending the hospital, under the surveillance system and processed for detection of E. histolytica.

Results

During the last two years about 2500 diarrhoeal samples were collected and screened for E. histolytica. About 3.6% were positive for E. histolytica. As compared to the earlier years, E. histolytica infection was observed to be less amongst patients screened during the last two years. No seasonality was observed in Kolkata although in the neighboring tropical country Bangladesh, a typical seasonality of E. histolytica infection was noticed.

Conclusion

The study indicates that the detection rate of E. histolytica infection amongst diarrhoeal patients in Kolkata is decreasing during the last two years than that of Bangladesh.

Background

Amoebiasis caused by infection with E. histolytica occurs almost all over the world and is highly endemic especially in the developing countries. It is one of the major causes of dysentery/diarrhoea in Kolkata, India. According to our previous study (unpublished), detection of Entamoeba histolytica showed a marked seasonality, i.e. high peak during post-monsoon and post-winter seasons. According to the reports from other tropical countries, especially in Bangladesh, which is geographically closest to Kolkata, there is a typical pattern of detection of E. histolytic w here E. histolytica usually shows its highest peaks in the wet season and gradually decreases with the arrival of dry season [1, 2]. In a study in Bangladesh, it was shown that wet environment is not the only factor that affects the detection curve of E. histolytica, but anti-Carbohydrate Recognition Domain IgA level in the gut is another determining factor for its occurrence in a closed population [3]. However, even in that case E. histolytica detection followed a particular seasonality and trend. However in Kolkata the present scenario is different from other tropical regions.

Study design and results

For the last few years, we have been engaged with the surveillance study to determine the detection rate of common enteric parasites in Kolkata. During the last two years, about 2500 diarrhoeal stool samples were screened from hospitalized patients through a systematic sampling procedure as described previously[1] in collaboration with Infectious Diseases Hospital, Kolkata. In this surveillance, every fifth patient attending the Infectious diseases hospital from different parts of Kolkata with diarrhoea in randomly selected two days a week were included in the study. Fecal samples from these patients were collected and sent to the laboratory within half an hour of collection for detection of E. histolytica by microscopic examination using iodine wet mount method; PCR and antigen capture ELISA. The whole study was carried out from the month of November 2007 to October 2009 to include at least two seasonal cycles for better understanding of the seasonality. Although one of the major diarrhoea causing pathogen in Kolkata is Vibrio cholerae[4] among all etiologies, E. histolytica (3.6%) is one of the major diarrheagenic parasites among the parasitic etiologies of diarrhoea. It caused some sporadic diarrhea throughout the study period without any particular seasonality which is uncommon for a tropical area like Kolkata. Overall a decreasing trend of E. histolytica infection was also seen (Figure 1). Reasons behind this different nature of infection might be due to physical and environmental factors which could influence E. histolytica detection rate, such as choice of common antimicrobial drug, temperature, detection procedure of E. histolytica etc. But none of these changed strikingly in last two years that could affect E. histolytica detection rate. Indiscriminate use of anti-parasitic drugs like metronidazole and tinidazole could be attributed to the decreasing trend of detection of E. histolytica in Kolkata.

Figure 1
figure 1

Month wise distribution of samples collected throughout the study period along with percentage of E. histolytica positive among them.

Conclusion

The present study demonstrates that there is no particular seasonality of occurrence of E. histolytica infection which is not typical of a tropical area like Kolkata. A different pattern which is almost unique in comparison to other tropical countries has been observed. Contribution of environmental and host factors as well as parasite genotypes are very important for the outcome of infection [2, 5]. Although no physical or environmental factor behind this changing pattern of E. histolytica infestation in Kolkata has yet been reported, but it is certain that E. histolytica is showing a slow but obvious change in its seasonality and this might be a signal for a transition period of changing nature of infestation by this parasite in this part of the world. It is worth mentioning that impact of climate change might lead to such changes, although no such studies are available.

References

  1. Mukherjee AK, Chowdhury P, Bhattacharya MK, Ghosh M, Rajendran K, Ganguly S: Hospital-based surveillance of enteric parasites in Kolkata. BMC Research Notes. 2009, 2: 110-10.1186/1756-0500-2-110.

    Article  CAS  Google Scholar 

  2. Ravdin JI: Amebiasis; Series on Tropical Medicine. Science and Practice. 2000, Imperial College Press, 2: 55-10.1023/A:1017235624216.

    Google Scholar 

  3. Haque R, Mondal D, Duggal P, Kabir M, Roy S, Farr BM, Sack RB, Petri WA: Entamoeba histolytica Infection in Children and Protection from Subsequent Amebiasis. Infect Immunity. 2006, 904-909. 10.1128/IAI.74.2.904-909.2006.

    Google Scholar 

  4. Nair Balakrish Gopinath, Ramamurthy Thandavarayan, Bhattacharya Kumar Mihir, Krishnan Triveni, Ganguly Sandipan, Saha Rani Dhira, Rajendran Krishnan, Manna Byomkesh, Ghosh Mrinmoy, Okamoto Keinosuke, Takeda Yoshifumi: Emerging trends in the etiology of enteric pathogens as evidenced from an active surveillance of hospitalized diarrhoeal patients in Kolkata, India. Gut Pathogen. 2010, 2: 4-10.1186/1757-4749-2-4.

    Article  Google Scholar 

  5. Petri WA, Mondal D, Peterson KM, Duggal P, Haque R: Association of malnutrition with amebiasis. Nutr Rev. 2009, 67: S207-10.1111/j.1753-4887.2009.00242.x.

    Article  Google Scholar 

Download references

Acknowledgements

This study was supported by grants from

1. Japan Health Science Foundation and

2. Okayama University Program of Founding Research Centre for Emerging and Reemerging Infectious Disease, Ministry of Education, Culture, Sports, Science and Technology of Japan.

Authors also acknowledge the help and support given by Prof. Y. Takeda, Dr. G. B. Nair, Dr. Samiran Panda and Dr. K. Rajendran of NICED during preparation of this letter and Debarati Ganguly of Calcutta University for her careful proof reading and correction of English in the letter.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Sandipan Ganguly.

Authors’ original submitted files for images

Below are the links to the authors’ original submitted files for images.

Authors’ original file for figure 1

Rights and permissions

This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Reprints and permissions

About this article

Cite this article

Mukherjee, A.K., Das, K., Bhattacharya, M.K. et al. Trend of Entamoeba histolytica infestation in Kolkata. Gut Pathog 2, 12 (2010). https://doi.org/10.1186/1757-4749-2-12

Download citation

  • Received:

  • Accepted:

  • Published:

  • DOI: https://doi.org/10.1186/1757-4749-2-12

Keywords