BAU study uncovers deadly parasites in slum

A group of researchers from the Department of Parasitology at Bangladesh Agricultural University (BAU) has identified several harmful intestinal parasites affecting both humans and animals. The study highlights crucial public health concerns and is expected to play a significant role in controlling these diseases.

The research team was led by Dr Md. Shahiduzzaman, professor at BAU’s Department of Parasitology, with graduate student Beni Amin also actively involved in the study.

Explaining the research methodology, Beni Amin said the study was conducted in a densely populated slum area near the Railway Colony in Mymensingh city. A total of 102 samples were collected from humans (children and elderly), poultry, cattle, goats, pigeons, water sources, and soil. The DNA from these samples was extracted in the lab and analysed using PCR and sequencing to identify pathogens.

Dr. Shahiduzzaman explained that the research revealed three major intestinal parasites known to cause diarrhea in humans—Cryptosporidium, Blastocystis, and Giardia. By analysing the genetic makeup of these parasites, the researchers found that certain subtypes can transmit between animals and humans, and vice versa. Among these, Blastocystis showed the highest prevalence, being detected in 24 samples. While its presence in humans was limited, it was widely found in goats, cattle, and poultry. Remarkably, Blastocystis was found in 100 per cent of goat samples. The study identified seven different subtypes of this parasite: ST2 and ST3 were found only in humans, while ST23 and ST24 were exclusive to animals and birds. Identical subtypes were found in both goats and poultry from the same household, suggesting interspecies transmission.

Professor Shahiduzzaman emphasised that the detection of similar subtypes in multiple animal species strongly indicates the potential for cross-species transmission.

Cryptosporidium was detected in eight samples—one from a human subject, in which a specific subtype of Cryptosporidium parvum was identified, typically transmitted from animals to humans. Additionally, this parasite was found in three goats and three chickens. One soil sample contained Cryptosporidium meleagridis, a bird-associated species.

Giardia intestinalis was found in only one soil sample, which the professor believes originated from human or animal fecal contamination.

Regarding the causes of these infections, Professor Shahiduzzaman pointed to unplanned sanitation systems, the unrestricted movement of animals, and unhygienic conditions in the slum area. These create an ideal environment for the spread of parasites, placing both animals and humans at risk. Contaminated soil and water were found to be key transmission routes. Livestock feeding on garbage, for instance, may get infected and later transmit the parasites to humans through direct or indirect contact. Water from ditches, ponds, or drains contaminated with feces can also spread these pathogens during bathing, washing clothes, or cleaning utensils.

On raising awareness and prevention, Dr. Shahiduzzaman stressed the importance of improving sanitation and promoting hygiene in densely populated slum areas. He called for designated areas for animal waste disposal, planned sanitation systems, and widespread public awareness to help prevent such infections.

Addressing the limitations and future scope of the study, professor Shahiduzzaman said, “This was a pilot study conducted on a small scale. However, the findings provide valuable data for larger and more extensive research in the future. If similar studies are conducted in other slum areas, rural regions, and overcrowded urban neighborhoods, we could gain a clearer picture of the actual situation regarding parasitic infections. With proper support from government and non-government organisations, we aim to expand our research further.”

He concluded by saying that the study represents a significant step forward in public health research in Bangladesh and reinforces the need to adopt a ‘One Health’ approach—considering humans, animals, and the environment as interconnected. Successful prevention of parasitic infections will require safe water, proper animal management, effective waste disposal, and mass public awareness.