Loa loa

Definition

Loa loa, also known as the African eye worm, is a parasitic nematode that infects humans and can cause a range of skin and eye-related conditions. It is primarily found in certain regions of West and Central Africa and is transmitted through the bites of infected deerflies.

5 Must Know Facts For Your Next Test

1. Loa loa infections are characterized by the presence of adult worms that can migrate through the subcutaneous tissues, often causing localized swelling and discomfort known as Calabar swellings.
2. The adult worms can also occasionally cross the conjunctiva of the eye, leading to the characteristic symptom of the 'eye worm' or ocular larva migrans.
3. Loa loa infections can also lead to more severe complications, such as encephalopathy, a potentially life-threatening condition that can occur when microfilariae (immature worms) are rapidly killed by treatment.
4. Diagnosis of Loa loa infection typically involves the identification of the adult worms or microfilariae in the blood or skin, as well as serological tests to detect antibodies.
5. Treatment for Loa loa infections often involves the use of anthelmintic drugs, such as diethylcarbamazine or ivermectin, which can effectively kill the adult worms and microfilariae.

Review Questions

• Describe the life cycle of the Loa loa parasite and how it is transmitted to humans.
  • The Loa loa parasite has a complex life cycle that involves two hosts: humans and deerflies. The adult worms live in the subcutaneous tissues of infected humans, where they mate and produce microfilariae (immature worms) that circulate in the bloodstream. These microfilariae are then ingested by deerflies during a blood meal. Inside the deerfly, the microfilariae develop into infective larvae, which are then transmitted back to humans when the deerfly takes another blood meal. Once inside the human host, the infective larvae mature into adult worms, completing the cycle.
• Explain the clinical manifestations and complications associated with Loa loa infections.
  • Loa loa infections can lead to a range of clinical symptoms, including the characteristic 'eye worm' or ocular larva migrans, where the adult worms can be seen moving under the conjunctiva of the eye. Infections can also cause localized swelling and discomfort, known as Calabar swellings, as the adult worms migrate through the subcutaneous tissues. In some cases, more severe complications can arise, such as encephalopathy, a potentially life-threatening condition that can occur when microfilariae are rapidly killed by treatment, leading to a sudden increase in the number of circulating microfilariae and an inflammatory response in the central nervous system.
• Discuss the diagnostic and treatment approaches for Loa loa infections, and the importance of considering potential complications during management.
  • Diagnosis of Loa loa infections typically involves the identification of the adult worms or microfilariae in the blood or skin, as well as serological tests to detect antibodies. Treatment for Loa loa infections often involves the use of anthelmintic drugs, such as diethylcarbamazine or ivermectin, which can effectively kill the adult worms and microfilariae. However, it is crucial to consider the potential for complications, such as encephalopathy, during treatment, as the rapid killing of microfilariae can lead to a sudden increase in their numbers and a potentially life-threatening inflammatory response in the central nervous system. Careful monitoring and management of these complications are essential to ensure the safe and effective treatment of Loa loa infections.

Related terms

Onchocerciasis: A parasitic infection caused by the nematode Onchocerca volvulus, which is transmitted by blackflies and can lead to river blindness.

Filariasis: A group of diseases caused by parasitic filarial worms, including Loa loa, which can lead to lymphatic system damage and elephantiasis.

Deerfly: A type of biting fly that can transmit the Loa loa parasite to humans through its blood-feeding behavior.