There are so many infectious diseases that affect the majority of the world’s population. These infectious diseases are mostly communicable and can be transmitted from person-to-person, person-to-animal animal or animal-to-person. Some infections are more prevalent in certain populations due to the state of their health, job, lifestyle choices, etc. The purpose of this writing is to educate the world on Balantidiasis in immunocompromised patients

Introduction

Balantidiasis is a zoonotic disease caused by Balantidium coli, a ciliated protozoan that normally affects the large intestine.¹ B. coli is the largest intestinal parasitic protozoan parasite in both humans and other mammals. It is considered a parasite because it depends on its host for survival and does nothing to help the host but rather harms it. 

The infection is normally associated with pigs and is transmitted to humans through the orofecal route, especially in areas where there is poor sanitation, such as slums, rural areas, prison facilities, etc. Because pigs are an animal reservoir for this disease, human cases are more common in areas where pigs are kept.

The clinical symptoms can vary from no symptoms at all to long-term loose stool and dysentery.² The illness can potentially worsen and result in a severe case of gastroenteritis, which is an extreme case of stomach irritation and inflammation. 

Parts of B. Coli that help them to function

The parasite uses cilia to move and has macro- and micronuclei, feeding vacuoles, and red blood cells in its cytoplasm.² The trophozoite is B. coli's active feeding stage.

Trophozoites are oval-shaped and have the following measurements:

• Width: 40–50 μm
• Length: 60–70 μm

The peristome, which connects to the cytostome, is a depression in its front end. Trophozoites have two nuclei:

• A large macronucleus, shaped like a kidney, is responsible for normal metabolic functions
• A smaller micronucleus, which is spherical in shape and plays a role in preserving genetic material

To aid in their mobility and feeding, trophozoites have rows of beating cilia that cover their body.

The cytoplasm contains contractile vacuoles as well as food vacuoles containing consumed materials. The cyst is the pathogenic stage of B. coli. Cysts are round, having a diameter of 40–60 μm. They possess a strong, bilayered cyst wall.

The macronucleus, micronucleus, and contractile vacuoles comprise the granular cytoplasm.

Evasion of the immune system

After entering the host, the B. coli. Cells hide by finding some organs that are not patrolled by the immune system. The immune cells go through the majority of the body parts, detecting foreign materials and destroying them to prevent diseases. The purpose is to hide in these organs to avoid being detected and destroyed by the immune system. This evasion style helps them multiply by giving rise and causing harm without being seen. 

Are immunocompromised individuals at risk of B. Coli infections?

Immunocompromised people have weakened immune systems due to various conditions. These individuals do not have their immune system functioning normally and are vulnerable to such infections. 

• For example, in HIV patients, there is a low level of T-lymphocytes because the viral cells attack and destroy them. These T lymphocytes, in particular the helper T-cells, also referred to as CD8+, are immune cells that assist in coordinating actions to aid in the activation of other infection-fighting systems
• Also, certain medications, like those given during organ transplants and those given to cancer patients in cancer treatment, suppresses the immune system
• Pregnancy also leads to a weakening of the immune system by the body itself. This is to allow for the proper development and formation of the baby

People undergoing all these conditions are susceptible to many ranges of infections due to weakened immune responses, and as such, parasites like Cryptosporidium, Blastocystis, Microsporidium and Strongyloides pose a significant risk to their health.³ 

Clinical manifestations of balantidiasis

The most common manifestation is mild balantidiasis, which includes diarrhea and constipation. Balantidiasis comes in many forms, and they include:

• Acute balantidiasis with dysentery is present, accompanied by mucus, a strong urge to urinate, nausea, vomiting, stomach discomfort, and headaches. Such a situation is capable of rapid advancement and fulminance
• There is also chronic balantidiasis, which goes from mild infections to a chronic illness if left untreated. Symptoms include iron deficiency anemia, headaches, recurrent diarrhea, appetite loss, and weight loss
• Lastly, extraintestinal balantidiasis is extremely rare, however, it can present as appendicitis, genitourinary tract infections, or pneumonia
• Severe adverse effects can develop, especially in immunocompromised patients, and can be fatal if left untreated. These consequences include intestinal bleeding, perforation, and peritonitis

Epidemiology of balantidiasis

Human infection is primarily seen in areas of unsanitary and unfavorable environmental conditions, such as poorer nations and those in tropical and subtropical climates. 

Available data show that the main geographical regions in which the parasite is found are the Pacific Islands, the Philippines, Papua New Guinea, South and Central America, and Central Asia. In humans, the prevalence of B. coli may range from 0.02% to 1%. Given that the parasite is usually asymptomatic and underreported, these low numbers are not representative of its actual presence and prevalence. 

Human infections have been found to be more common in a number of places, including the Middle East, Papua New Guinea, the Philippines, and Latin America; among pig farmers, rates of the infection have been as high as 29%. ² There is little information on the prevalence of balantidiasis in Africa, where it is regarded as a neglected tropical disease. 

Nonetheless, several studies have indicated that certain African nations have a higher prevalence of Balantidium coli infection. Within the communities studied in Ethiopia, a study indicated a prevalence of 47.5% for balantidiasis;⁴ in Ghana's Ga West Municipality, the general prevalence was 10.4%, with direct pig producers being highly infected.⁵

Pathogenesis and clinical manifestations

Cysts are the stage that transmits the balantidiasis. The host usually gets the cyst by consuming contaminated food or water. Once inside the body, the cyst hatches in the small intestine, and the trophozoites move into the large intestine. These trophozoites stay in the large intestine and appendix of both humans and animals, reproducing through binary fission. Trophozoites undergo encystation to form infective cysts. Some trophozoites enter the colon wall and reproduce, resulting in ulcerative disease. Some dissolve after returning to the lumen. Mature cysts are carried through feces.⁶ The trophozoites secrete powerful enzymes that help them move through the intestinal wall and cause ulcers in the colon. Balantidium coli relies on this method of invading and damaging tissues to cause harm to people.

Diagnosis of balantidiasis in immunocompromised patients

• The simplest way of detecting the cysts of B. coli is via microscopy. The cysts, trophozoites, or both, can be microscopically identified by thoroughly inspecting the stool. The method is repeated using stool samplings a few days apart, as parasites are excreted at different times and amounts to establish the presence of an infection
• Also, rectoscopy or endoscopy with a colorectal swab or specimen collection from the colorectal mucosa may be required for parasitologic testing⁷ 
• Serologic testing
• PCR and other powerful tools can be employed to detect the presence of infection in an individual

Treatment strategies

Medications such as iodoquinol, metronidazole, and tetracycline are the three most often prescribed treatments for Balantidium coli.⁵ The primary therapy for B. coli is Tetracycline with a dosage of 500 mg orally four times a day for ten days, followed by metronidazole (500 -750 mg tablets 3 times a day for 5 days). As an alternative to tetracycline, take iodoquinol 650 mg orally three times daily for 20 days. Another therapeutic option is Paromomycin Sulfate (PS), whose smallest dosage that worked is 25 mg/day for 5 days, after a 2-day rest, followed by another 5 days. 

Some things to note

• Tetracycline should not be taken during pregnancy, and children under eight years old should be given other drugs
• Metronidazole is secreted in breast milk; thus, caution should be used during lactation
• It is not entirely established whether iodoquinol and paromomycin are safe for children
• In cases of severe fulminant colitis, surgery may occasionally be required in addition to antimicrobial medication

Prevention and control measures

As an individual, the best ways to protect yourself from Balantidium coli infections include:

• Through practicing personal hygiene
• Drink from clean water sources
• Eating well-cooked foods

For large populations, such as cities and countries, there must be public health efforts by the government and other regulatory bodies to lower the prevalence of balantidiasis. Some of the interventions include:

• Monitoring water system sources to prevent contamination with human and pig feces
• Public health surveillance should be instituted to track infections

Summary

• The largest intestine parasite protozoan, Balantidium coli, is the cause of the zoonotic disease balantidiasis. It is usually associated with pigs, and it is transmitted to humans through the orofecal route, especially in poor hygienic conditions. The gastroenteritis might appear with mild to serious clinical symptoms. Less competent immune systems are more readily prone to developing an infection in instances such as surgical operations, organ transitioning, pregnancy, etc.
• The screening of immunocompromised patients by healthcare providers should be thorough, and it should not exclude asymptomatic ones, because they might as well have a case of balantidiasis. Treatment options should be discussed with the doctor if such patients are diagnosed

Some medications Tetracycline, metronidazole, and iodoquinol, are a few examples of drug treatments. Also, keeping oneself clean, eating properly cooked food, and drinking clean water are part of prevention. Critical measures in public health to monitor sources of water and conduct surveys should be employed to battle Balantidium coli infections.