Introduction
Hymenolepis nana, also known as dwarf tapeworm, is the most common tapeworm worldwide and affects the offspring or children of four to ten years more than the adults. It is the tiniest tapeworm affecting human beings. This tapeworm is common in warm places, such as India, Latin America, Russia, and South Europe. However, the primary cause of infection is the improper maintenance of hygiene.
What Is the Mode of Transmission of Hymenolepis Nana Infection?
An individual can get infected with dwarf tapeworm infection by ingesting eggs, contaminated food or water, touching the mouth with contaminated fingers, intaking the contaminated soil, or ingesting an infected arthropod.
What Does a Dwarf Tapeworm Look Like?
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The dwarf tapeworm Hymenolepis nana is a little worm measuring 40 mm long and 1 mm wide. It is a ribbon-shaped worm with a thick cuticle layer on top, protecting it from host enzymes, and has a large surface area for absorbing food.
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The scolex (anterior end of the tapeworm) has a rostellum (a small process resembling a beak) with a circle of 20 to 30 hooks. In addition, it has four suckers.
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The neck is long and thin. There are unilateral genital pores, and each contains three testicles.
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The gravid portion (the part containing eggs) deteriorates and discharges eggs after apolysis (separating the cuticle from the epidermis in arthropods). These eggs measure around 30 to 45 mcm in width.
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The oncosphere (larval form of a tapeworm) is surrounded by an external filmy later and a thick inner layer with polar thickening and filaments.
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The embryophores (outer covering of the tapeworm) that contribute to the striated appearance of the eggs are inadequate.
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The rostellum is invaginated, but its hooklets resemble tuning forks.
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The strobila (segmented part of the body of a tapeworm) has short proglottids (segments) followed by developed ones.
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Each proglottid contains male and female reproductive structures, indicating dwarf tapeworm is a hermaphroditic (bisexual). In addition, each fragment has an ovary and three testicles.
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The proglottid contains fertilized eggs, which get expelled when the proglottid gets old and cannot take in nourishment. These eggs can settle in the tiny intestinal microvilli and hatch.
Does Hymenolepis Nana Require an Intermediate Host for Transmission?
Studies carried out in 1887 have shown that dwarf tapeworm does not require an intermediate host to transmit infection among rats. However, bugs were found to be the intermediate host for transmission among human beings.
What Is the Pathogenesis of Hymenolepis Nana?
The tapeworms do not have a digestive system and feed by taking in nutrients from the intestinal lumen. They require carbohydrates and absorb the substances passing through the intestine. The worm gets attached to the intestinal walls with the rostellum and suckers when it becomes an adult.
A person gets infected from the eggs in the infected person's fecal matter. The eggs then incubate in the duodenum, releasing the oncosphere (larval form of a tapeworm), which penetrates the mucosa and lies in the lymph channels. An oncosphere transforms into a cysticercoid with a scolex and a tail. The cysticercoids enter the small intestinal lumen, where they join and develop. They can develop more at high temperatures and inside the larval insects and bugs.
The most well-known means of contamination in humans is through eggs. However, a few infection cases spread by ingesting infected bugs or insects.
The spread of dwarf tapeworms is more due to their short lifespan and quick course of action.
What Are the Signs and Symptoms of Hymenolepis Nana?
Light infections are usually asymptomatic. However, severe infections have the following symptoms.
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Anorexia.
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Intestinal inflammation.
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Nausea.
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Loss of appetite.
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Abdominal pain.
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Weakness.
Young children usually show the following symptoms.
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Difficulty sleeping.
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Itchy buttocks.
How to Diagnose Dwarf Tapeworm Infection?
The dwarf tapeworm can be identified from eggs in the stool. Therefore, the stool specimens might be collected and submitted for several days to diagnose the condition.
How to Treat Hymenolepis Nana Infection?
Praziquantel is recommended for patients experiencing Hymenolepis nana infection. It is a bacteriocidal drug that is safe, effective, and tolerated. The tablet must be taken with food and water. Albendazole can replace the drug.
Certain studies revealed the following concepts.
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Hymenolepis nana, in its cysticercoid phase, is most susceptible to Praziquantel.
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Praziquantel shows morphological changes in the dwarf tapeworm.
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After ten minutes of Praziquantel's administration, the tapeworms were dead.
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The tapeworms were expelled from the caecum after 30 minutes of Praziquantel administration.
What Are the Risk Factors for Hymenolepis Nana Infection?
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Poor sanitation.
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Lack of human waste and garbage disposal.
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Present of insects in the environment.
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Poor hygiene practices while cooking.
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Nesting of rats.
How to Prevent Hymenolepis Nana Infection?
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Keep the surroundings clean.
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Do not allow water to stagnate.
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Avoid drinking contaminated water.
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Check if arthropods are growing in nearby regions.
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Wash hands with soap and water before eating, after eating, preparing food, using the toilet, and changing diapers.
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Teach children the significance of handwashing to prevent unnecessary contamination of infection.
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Cook or peel raw vegetables or fruits with clean water before eating.
Conclusion
As dwarf tapeworm infections are caused due to poor hygiene and sanitation, it is better to follow proper hygiene and maintenance in the environment. In addition, the infection is most common in children. Hence, they must be properly cared for and taught about maintaining hygiene in their surroundings. The prevention and control of the infection through hygiene practices are especially to breaking the disease cycle epidemiology. The healthcare professional also collaborates to control and demolish the infection for the people’s welfare.
