Halicephalobus Gingivalis Infection - Symptoms, Diagnosis, and Treatment

Introduction

Halicephalobus gingivalis infection is caused by Halicephalobus gingivalis. Halicephalobus gingivalis is a rare free-living saprophytic nematode found in water, soil, manure, and decaying organic matter. Stefanski named the nematode in 1954. It belongs to the nematode Rhabditia. Halicephalobus gingivalis is also known as Micronema deletrix. It is a parasite of the horse, invading the nasal cavity and other body areas to produce granulomatous masses. In rare cases, it can also affect humans in the form of fatal meningoencephalomyelitis (disease of the brain). The condition usually occurs in the body cut in the skin and moves through the bloodstream affecting various organs like the brain, spinal cord, and eyes. It is typically seen in individuals with a weakened immune system. Halicephalobus gingivalis infects vertebrates (a creature with a spine or backbone) and is morphologically different from several other species. It has a worldwide distribution but is common in Europe, North America, and Northeast Asia.

What Is the Morphology of Halicephalobus Gingivalis?

The morphology of Halicephalobus gingivalis is as follows:

• Halicephalobus gingivalis is present in distinctive rhabditiform esophagus with corpus isthmus, bulb, and reproductive tract. These are didelphic (possess two wombs) with diversified ovaries at the posterior end.

• There are only female worms in the tissue. Adults are 235 to 460 um long.

• In an adult, the posterior branch forms a short ovary, whereas the anterior branch becomes a combined uterus-oviduct (a tube-like structure that combines the uterus with the ovary).

• Eggs are oval, elongated, thin-shelled, and colorless. The larvae are small and have the same features as fully-developed worms. The worm has a conical, asymmetrical small tail that is shorter on the ventral side.

What Is the Mode of Infection of Halicephalobus Gingivalis Infection?

The mode of infection is as follows:

• The mode of infection is through the contamination of oral mucosa or skin wounds of the human body with the nematode. The site can be a preexisting lesion in the skin.

• The nematode enters the skin through open wounds and is carried to the other body parts through the bloodstream in blood and lymph. It may be transmitted through the optic nerve.

• Nematodes enter the central nervous system (CNS) through blood vessels, causing necrosis and inflammation. The brain is the most commonly involved site, followed by other organs like the kidney, oral cavity, nasal cavity, lymph nodes, and spinal cord.

What Are the Causes of Halicephalobus Gingivalis Infection?

The causes are as follows:

• The infection is more prevalent in areas with poor sanitation.

• People travel to areas where the prevalence of the disease is more.

• The population shifted from disease-prone areas to disease-free areas.

• Workers working in the soil are more prevalent to the disease because the nematode is soil-borne.

What Are the Clinical Features of Halicephalobus Gingivalis Infection?

The symptoms are as follows:

• Halicephalobus gingivalis infection is rare in humans and more common in horses. The symptoms of humans and horses are different.

• In humans, involvement of the brain is one of the most clinical manifestations of the disease-causing the fatal outcomes.

• The most common disease associated with the infection is meningoencephalomyelitis (an inflammatory disease of the central nervous system).

• The general symptoms include a change in the mental state, lethargy (lack of energy), and fever.

• Signs are facial deformation and firm swellings in the maxilla, unilateral and bilateral nasal discharge, difficulty in eating, weight loss, dyspnea (difficulty in breathing), and stridor (a harsh noise while breathing due to the obstruction of the windpipe).

• In horses, brain involvement is followed by kidneys, oral cavity, nasal cavity, lymph nodes, lungs, spinal cord, heart, liver, stomach, and adrenal glands.

• Symptoms include granulomatous nephritis and extensive tissue destruction.

What Is the Diagnosis of Halicephalobus Gingivalis Infection?

There are different diagnoses to diagnose the disease. The diagnosis is as follows:

1. Complete Blood Count (CBC) Test - The test will find the inflammation in the body. Elevated White Blood Cells (WBCs) and lymphocyte predominance in the cerebrospinal fluid (CSF) will be seen in a blood test. The other findings are infiltration of inflammatory cells in the liver and lungs.

2. Pathological Findings - The findings include edema (fluid filled in the surrounding tissues) and focal hemorrhage (bleeding from the blood vessels in the brain).

3. Histopathological Findings include perivascular acute and chronic inflammation (inflammatory disease of the central nervous system) and multinucleated giant cells.

4. Biopsy - The test from the right temporal lobe shows chronic active meningoencephalitis (inflammation of the brain's membranes) with focal chronic granulomatous vasculitis (inflammation of the cutaneous blood vessels).

5. Polymerase Chain Reaction is used to detect parasite Deoxyribonucleic acid (DNA) in brain tissues.

What Is the Treatment of Halicephalobus Gingivalis Infection?

Most human bodies are found only post-mortem (examination of dead body), so had been causing the death of humans. The humans had not been treated with antihelminthic drugs like Ivermectin and Benzimidazole. Scientists are researching the treatment of the disease. In animals like horses, the infection has been treated with Ivermectin alone or in combination with Diethylcarbamazine. But in most cases, they are ineffective because they do not cross the blood-brain barrier.

How Can the Disease Be Prevented?

The disease can be prevented by following measures.

• Proper pasture management (land covered with grass used for grazing animals).

• Handing off the waste.

• Proper care should be taken by the workers working in the soil.

• Maintenance of personal hygiene.

• Workers should wash their hands after working in the soil.

• Prevention of horses from the marsh (a type of wetland along the rivers and lakes) and swampy (a type of wetland that forms nearby forested areas or nearby water sources).

Conclusion

Halicephalobus gingivalis infection is a rare fatal disease. There is no proper diagnosis and treatment of the disease. Scientists are researching to prevent and cure the disease. Though the infection is soil-borne, people must take preventive measures to protect themselves. People should avoid visiting areas where the disease is more prevalent. The health care professionals, including doctors, and a nurse must conduct camps in the areas to educate the people about disease outcomes and preventive measures. The people in the community should maintain personal hygiene and proper hand washing. People must do proper waste management.