Medical Parasitology - Refugee Health
The Refugee Health Program at DSHS ceased operations on January 31, 2017. Refugee health services in Texas are now administered by the U.S. Committee for Refugees and Immigrants’ (USCRI). The Parasitology team at the DSHS Austin Laboratory examines specimens collected by the USCRI Medical Screening Program.
Loiasis
Loiasis is an infection caused by the parasitic roundworm Loa loa, commonly referred to as the African eye worm. The species is endemic to several western and central African countries and is rarely found elsewhere. The roundworm is spread by the repeated biting of infected Chrysops flies (known as deerflies, mangrove flies, or mango flies). The microfilariae, a motile egg stage of L. loa, enter the fly bite wounds and mature into adult worms below theskin. Liases infections are often asymptomatic but adult worms may cause localized and recurrent painful swelling that can develop over several years. The most visible sign of infection is when a roundworm travels across the sclera of the eye, causing pain and inflammation to the host. For more information on Loiasis, visit CDC - DPDx - Loiasis.
Loiasis Testing at DSHS Austin Laboratory
The DSHS Austin Laboratory’s Parasitology Team tests specimens for the presence of L. loa as part of the Refugee Health Services in Texas. Refer to the DSHS LTSM test menu for more details about Loa loa testing at the Laboratory.
Schistosomiasis
Schistosomiasis (snail fever, bilharziasis) is caused by several species of Schistosoma flatworms. Three main species infect humans: Schistosoma haematobium, S. japonicum, and S. mansoni. Transmission can occur when humans are exposed to freshwater sources that are contaminated with Schistosoma parasites.
People infected with Schistosoma flatworms shed eggs in their urine or stool. In fresh water, immature flatworms called miracidia hatch from eggs. The miracidia find and penetrate the tissues of freshwater snails where they mature into an infective stage known as cercariae. The free-swimming cercariae are released from the infected snail into the surrounding water. Cercariae enter their human host by burrowing though skin that is exposed to the contaminated water. Once inside the host’s body, the parasites travel to the liver. The male and female parasites migrate to either the lower intestines or bladder, where they release eggs into feces or urine.
Symptoms of schistosomiasis are a result of the body’s immune response to the flatworms. Symptoms include itching at the cercariae entry sites, fever, cough, abdominal pain, diarrhea, and enlargement of the liver and spleen. In some cases, infection may lead to lesions in the central nervous system.
For more information on Schistosomiasis, visit CDC - DPDx - Schistosomiasis Infection.
Schistosomiasis Testing at DSHS Austin Laboratory
The DSHS Austin Serology team tests serum specimens for the presence of antibodies to Schistosoma as part of the Refugee Health Services in Texas. Please refer to the DSHS LTSM test menu for additional information on Schistosoma species testing at the Laboratory.
The DSHS Austin Laboratory's Parasitology Team also performs Schistosoma species testing on both urine and fecal specimens.