WBR0084
| Author | PageAuthor::Kalsang Dolma |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Microbiology |
| Sub Category | SubCategory::General Principles |
| Prompt | [[Prompt::A 28 year old female immigrant from Africa presents with complaints of an itchy swelling over her entire body. She is also concerned about body aches. On physical examination, non-tender swelling is noted over her the limbs on the right side of her body. Laboratory findings show eosinophilia. Microscopic examination of the blood shows the microfilaria of loa loa, and a diagnosis of loa loa filiariasis is made. The vector for this condition is:]] |
| Answer A | AnswerA::Black fly |
| Answer A Explanation | [[AnswerAExp::The black fly is the vector for onchocerciasis.]] |
| Answer B | AnswerB::Soft tick |
| Answer B Explanation | [[AnswerBExp::The soft tick is a vector for relapsing fever.]] |
| Answer C | AnswerC::Hard tick |
| Answer C Explanation | [[AnswerCExp::The hard tick is a vector for lyme diseae, rocky mountain spotted fever, babesiosis, ehrlichiosis, tick-borne meningoencephalitis, colorado tick fever, Crimean-Congo hemorrhagic fever, and tick paralysis.]] |
| Answer D | AnswerD::Deerfly |
| Answer D Explanation | [[AnswerDExp::Deerfly is the vector of loa loa.]] |
| Answer E | AnswerE::Sandfly |
| Answer E Explanation | [[AnswerEExp::Sandfly is the vector for leishmaniasis.]] |
| Right Answer | RightAnswer::D |
| Explanation | [[Explanation::The deerflies (genus Chrysops) that transmit Loa loa bite during the day. Most people with loiasis do not experience signs or symptoms of infection, though persons who do not live in areas where the parasite is found, such as travelers to the area, are more likely to experience them. The most common manifestations of the disease are Calabar swellings and eye worm. Calabar swellings are localized, non-tender swellings usually found on the limbs and near joints. They are associated with itching that occurs in the area of the swelling or is generalized to the large areas of the body. Eye worm is the visible migration of the adult worm across the surface of the eye. Eye worm can be accompanied by eye congestion, itching, pain, and light sensitivity. Although eye worm can be very distressing, it usually lasts less than one week (often just hours) and commonly causes minimal damage to the eye. Other manifestations of disease include generalized itching, hives, muscle pains, joint pains, fatigue, and adult worms visibly migrating under the surface of the skin. Increased numbers of eosinophils are usually found on blood tests. Persons with long-term infection might develop kidney damage through immune complex deposition, though progression to chronic kidney disease is not common. Other uncommon manifestations include inflammation of the lymph glands, scrotal swellings, and lung infiltrates along with collections of fluid around the lung. Loiasis may also be associated with scarring of heart muscle. Educational Objective: The deerflies bites transmit the infectious organism loa loa that cause loiasis, a disease characterized by Calabar swellings and eye worm. |
| Approved | Approved::Yes |
| Keyword | WBRKeyword::Loa Loa, WBRKeyword::Infectious disease, WBRKeyword::Deerfly, WBRKeyword::Deerflies, WBRKeyword::eye worm |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |