This common parasite is harmless ... until it acts up in our gut
In the bustling urban landscapes of Malaysia, a microscopic intruder is making its presence felt. Blastocystis species (Blastocystis), a tiny single-celled parasite once overlooked, is now emerging as a health concern among the urban population.

With cases on the rise, it’s crucial to shed some light on this often-undiagnosed parasitic infection.

Blastocystis is a resilient microorganism, which can often be found in the gastrointestinal system of humans, as well as many animals.

This parasite often goes unnoticed because it doesn’t cause any symptoms in its host (asymptomatic), but for some individuals, it can lead to a range of gastrointestinal issues.

Indeed, most research on the human gut microbiota has shown that Blastocystis is a typical component of the healthy gut microbiota, that it is linked to higher bacterial populations, and that chronic asymptomatic infection is typical.

According to a systematic review conducted by myself and colleagues from other local universities, published in the Tropical Medicine and Infectious Disease journal last August (2023), 17.6% of the 9,596 stool samples from most states in Malaysia were found to contain Blastocystis.

Pahang had the highest frequency at 48.4%, followed by Selangor at 36.4%.

Numerous cases of Blastocystis infection have been documented in several Asian nations, with colonisation of the human gastrointestinal system reported as being as high as 100% in some developing countries.

Although humans and a few other animal species were the most frequently reported hosts, this parasite has also been found in various water sources.

In addition, there have been studies showing foodborne transmission of this parasite.

Be hygienic

Although it has not been confirmed how Blastocystis spreads, it is suspected to transmit through the oral-faecal route. Boiling drinking water is a simple and effective way of getting rid of disease-causing microorganisms such as parasites. — Filepic

This means that the parasite can spread through contact with the infected faeces of humans and animals, including via contaminated water and food.

Simple steps to prevent being infected by Blastocystis are proper and thorough handwashing, especially after visiting the toilet and changing diapers, and before preparing food; washing and peeling raw fruits and vegetables; and avoiding any food or water that might be contaminated.

The removal of this parasite from water sources can be challenging.

Some filters, like reverse osmosis (RO) systems and certain micron-rated filters, are more effective at removing microscopic organisms, including parasites.

RO systems are known for their ability to remove a wide range of contaminants, including parasites, but they can be relatively expensive and may have other limitations.

The cyst form (three to five micrometres) of Blastocystis is postulated to be the infectious stage.

To effectively remove these cysts, a filter with a pore size of one µm or smaller should suffice.

Filters with a pore size of 0.1 µm or smaller can provide extra protection against smaller protozoa.

Therefore, boiling water remains a fundamental practice to ensure the safety of our drinking water.

Its efficacy in killing or inactivating pathogenic (disease-causing) organisms, such as bacteria, viruses and parasites is well-documented.

Why so high?

Several key factors contribute to the increasing prevalence of Blastocystis in urban Malaysia. including:

Lack of awareness Many urban dwellers are still unaware of the potential health risks associated with this parasite. The absence of proper knowledge can lead to a lack of precautions and preventive measures.

Urban migration Rural-to-urban migration is a common occurrence. People from different regions bring their unique hygiene practices with them, contributing to the spread of the parasite in the urban melting pot.

Diverse food choices In the city, a vast array of food options is readily available. However, street food and processed goods may not always adhere to the highest hygiene standards.

Immune status of the host Populations with compromised immune systems are more vulnerable to the hosting and spread of Blastocystis.

Industrialisation typically contributes to an influx of migration.

Selangor has Malaysia’s highest rural-urban migration rate.

Thus, migration may be contributing to Selangor’s high Blastocystis presence, despite its higher socioeconomic status.

According to some studies, Malaysia’s social landscape is still changing, which means that migration will continue to increase.

The influx of foreign migrants is also increasing as the demand for foreign workers grows.

Many of these migrants have been found to have a high parasitic burden upon arrival in the country.

Symptoms and treatment

Our bodies often send us signals when something isn’t quite right. Thoroughly washing raw vegetables and fruits by immersing them in water and shaking off the excess is the best way to eliminate contaminates. — TNS

Gastrointestinal discomfort can be a common occurrence for many people.

Yet, there are times when these symptoms should not be brushed aside.

If you find yourself experiencing unusual stool consistency or persistent gastrointestinal issues, it’s essential to recognise that there may be an underlying cause, such as a Blastocystis infection, which requires medical attention.

Such gastrointestinal symptoms can range from mild discomfort to more severe issues, such as:

Diarrhoea: Frequent and loose bowel movements that may be accompanied by abdominal pain.

Constipation: Difficulty passing stool, which can lead to discomfort and bloating.

Abdominal pain: Cramping or discomfort in the belly region.

Nausea and vomiting: Feeling queasy or actually vomiting.

Unusual stool consistency: Stools that appear watery, contain blood, or have an unusually foul odour.

Weight loss: Unexplained weight loss, especially if it occurs rapidly.

Ignoring persistent or unusual gastrointestinal symptoms can have consequences.

Seeking medical help is crucial for several reasons:

Accurate diagnosis Gastrointestinal symptoms can be caused by various factors, ranging from infections to dietary issues. A doctor can conduct tests to determine the exact cause and provide a precise diagnosis.

Treatment If Blastocystis or another pathogen is responsible for your symptoms, it’s essential to receive appropriate treatment. In the case of symptomatic Blastocystis infection, anti-parasitic medications may be prescribed.

Preventing complications Certain gastrointestinal infections can lead to complications if left untreated. Prompt medical care can help prevent these complications from developing.

Peace of mind Knowing the cause of your symptoms and receiving treatment can bring relief and improve your quality of life.

Your health should always be a priority.

If you or a loved one is experiencing persistent or unusual gastrointestinal symptoms, don’t hesitate to consult a medical professional.

Discuss your symptoms, undergo any necessary tests, and follow the recommended treatment plan.

Remember, early intervention can lead to a faster recovery and a healthier, symptom-free future.

Don’t let gastrointestinal issues disrupt your life when there are medical experts ready to help you find the answers and solutions you need – your wellbeing is worth it.

Preventive measures, such as personal hygiene practices, consuming clean water and food, and proper handwashing, are vital in mitigating the risk of Blastocystis infection.

By addressing these issues and fostering a culture of awareness and accountability, urban Malaysians can effectively combat this silent intruder in their midst.

Dr Vinoth Kumarasamy is a parasitologist and lecturer at Universiti Kebangsaan Malaysia. For more information, email starhealth@thestar.com.my. The information provided is for educational and communication purposes only, and should not be considered as medical advice. The Star does not give any warranty on accuracy, completeness, functionality, usefulness or other assurances as to the content appearing in this article. The Star disclaims all responsibility for any losses, damage to property or personal injury suffered directly or indirectly from reliance on such information.
Wellness,Parasite,infectious diseases,blastocystis
Blastocystis often resides harmlessly in the human gastrointestinal system, but can sometimes make us ill.