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* Objective: To characterize the etiologic agent (WA1) of the first reported case of babesiosis acquired in Washington State. * Design: Case report, serologic, molecular, and epizootiologic studies. * Setting: South-central Washington State. * Patient: A 41-year-old immunocompetent man with an intact spleen who developed a moderately severe case of babesiosis. * Measurements: Serum specimens from the patient were assayed by indirect immunofluorescent antibody (IFA) testing for reactivity with seven Babesia species and with WA1, which was propagated in hamsters inoculated with his blood. A Babesia-specific, ribosomal-DNA (rDNA) probe was hybridized to Southern blots of restriction-endonuclease-digested preparations of DNA from WA1, Babesia microti, and Babesia gibsoni. Serum specimens from 83 family members and neighbors were assayed for lFA reactivity with WA1 and B. microti. Small mammals and ticks were examined for Babesia infection. * Results: The patient's serum had very strong lFA reactivity with WA1, strong reactivity with B. gibsoni (which infects dogs), but only weak reactivity with B. microti. DNA hybridization patterns with the rDNA probe clearly differentiated WA1 from B. gibsoni and B. microti. Four of the patient's neighbors had lFA titers to WA1 of 256. The tick vector and animal reservoir of WA1 have not yet been identified, despite trapping 83 mammals and collecting 235 ticks. * Conclusions: WA1 is morphologically indistinguishable but antigenically and genotypically distinct from B. microti. Some patients elsewhere who were assumed to have been infected with B. microti may have been infected with WA1. Improved serodiagnostic and molecular techniques are needed for characterizing Babesia species and elucidating the epidemiology of babesiosis, an emergent zoonosis., A new species of Babesia may have been the cause of the first reported case of babesiosis in Washington State. Babesiosis is a group of tick-borne diseases caused by infection with protozoa of the genus Babesia. This new species of Babesia is referred to as WA1. A 41-year-old man from south-central Washington was diagnosed with babesiosis. Blood samples from the patient were analyzed for reactivity to seven different species of Babesia and WA1. Blood samples from the patient and 83 family members and neighbors were also tested for reactivity to B. microti and WA1. The patient had very strong reactivity to WA1, strong reactivity to B. gibsoni and weak reactivity to B. microti. WA1 was genetically distinct from B. gibsoni and B. microti. Four of the patient's neighbors had reactivity to WA1.

Onchocerciasis is a disease caused by parasitic filarial worms, which are transmitted through bites of black flies. The disease is characterized by nodules in the skin, an itchy rash, and eye lesions. It is one of the world's leading causes of blindness. Researchers have suggested that the immune response to the worm is the major cause of the symptoms of this disease. However, individuals can also mount responses that make them immune to the disease. Onchocerciasis is common in Central and South America and in Africa. From a group of 1,146 long-term residents from five plantations in endemic areas of Guatemala, 778 individuals were confirmed as having onchocerciasis. (An endemic area is one in which a particular disease is always found, but does not cause high mortality.) In infected individuals, the nodules that contained adult worms were shown to contain antibody molecules, indicating that the individuals had mounted an immune response against the worm. The types of antibody were analyzed and found to be of two classes (isotypes) in the majority of individuals. The antibodies primarily reacted with proteins of the worm that were of low molecular weight. Of the individuals studied, 268 never developed disease; 44 of these individuals were from areas that were moderately to highly endemic. Because they are from endemic areas, these individuals are considered to be immune. It is hoped that further study of the immune individuals will allow the identification of the reasons why they did not develop disease, and may lead to methods of preventing onchocerciasis in others. (Consumer Summary produced by Reliance Medical Information, Inc.)

Onchocerciasis is a parasitic disease caused by filarial worms, which are transmitted through bites of black flies. The disease is characterized by nodules in the skin, an itchy rash, and eye lesions. Onchocerciasis is one of the world's leading causes of blindness. It is thought that the immune response to the worm is the major cause of the symptoms associated with the disease. However, individuals can also mount immune responses that prevent them from developing the disease. Onchocerciasis is common in Central and South America and Africa. Long-term residents (778) from endemic areas of Guatemala, who were confirmed as having onchocerciasis, were classified into clinical groups, based on whether they had a history of onchocerciasis and if they had skin nodules containing adult worms or immature worms in their skin. Individuals (44) who lived in the endemic area but never developed the disease were considered to be immune to onchocerciasis and were included in the study. The majority of infected individuals had higher levels of antibodies (molecules made against foreign agents) of two specific classes (isotypes) than uninfected individuals. The levels were highest in those who had adults worms in skin lesions and immature forms in their skin. Antibody of the specific isotype IgG3 was formed against a particular antigen, (a molecule that is recognized as foreign) designed GP20, in the majority of individuals who had immature forms of the worm in their skin. It is this immature form of the worm that is infectious. It is hoped that the identification of a molecule that is recognized as foreign in infected individuals can be developed as a therapeutic agent to prevent disease. (Consumer Summary produced by Reliance Medical Information, Inc.)

Filariasis is a disease that is caused by filarial nematode worms. Wuchereria bancrofti (W. bancrofti) is a filarial nematode that is found in tropical climates; it can be transmitted to humans by the bite of an infected mosquito. Once inside the body, the worms can travel in the blood to various body tissues and to the lymph vessels. While the worms are alive they do not pose a serious threat and may not produce any symptoms. However, when the adult worms die they clog or plug blood and lymph vessels. This can cause inflammation and tissue damage (scaring). In severe cases, elephantiasis (elephant leg) may occur as blood and lymph vessels become clogged with dead worms. Ivermectin and diethylcarbamazine (DEC) have been used to treat patients with filariasis. Both drugs cause fever and muscle pain. While some studies have reported that a single dose of ivermectin may be as effective as 12 days of treatment with DEC, other studies have suggested that DEC may be more effective than ivermectin in treating filariasis. This study was conducted to evaluate the effectiveness of both drugs in treating filariasis. Thirty adult Haitians with filariasis were given a single dose of ivermectin, followed by either one dose of ivermectin, two doses of ivermectin, or 12 days of treatment with DEC. The effectiveness of the drugs was determined by measuring the amount of parasite antigen present in the blood before and after each treatment. DEC reduced the amount of parasite antigen by 75 percent, while ivermectin produced a 34 percent reduction. These results demonstrate that a single dose of ivermectin, followed by a 12-day course of DEC, is the most effective treatment for filariasis. (Consumer Summary produced by Reliance Medical Information, Inc.)