Ocular toxocariasis typically occurs in 5- to 10-year-olds. Usually a single eye is affected. Symptoms include strabismus, unilateral decreased vision, and leukokoria.
Enzyme-linked immunosorbent assay (ELISA) is 78% sensitive and 92% specific for the diagnosis of visceral toxocariasis. However, the sensitivity is lower for ocular toxocariasis. The disease cannot be diagnosed from stool, as the eggs are not excreted by humans, said Dr. Cantey.
Mild toxocariasis often does not need treatment. Visceral disease is treated with 5 days of albendazole; corticosteroids may be used for allergic symptoms. Ocular toxocariasis is treated with 2-4 weeks of albendazole, along with aggressive anti-inflammatory treatment with corticosteroids, and surgery. Albendazole is not approved by the FDA for this indication.
Trichomoniasis
Trichomonas vaginalis is a parasite that is spread through sexual contact. It’s estimated that there are 5-7 million cases yearly in the United States. However, the prevalence may be as great as 20 million. The rate is 10-fold greater among black women, compared with non-Hispanic white women (13.3% vs. 1.3% respectively).
Patients with trichomoniasis can be asymptomatic. In women, symptoms include vaginal discharge, pruritus, and dysuria; in men, symptoms include urethral discharge and dysuria.
Physical examination may reveal mucopurulent discharge, "strawberry cervix" (colpitis macularis), cervical erythema, or cervical friability.
T. vaginalis infection can cause premature rupture of membranes in pregnant women, preterm birth, low birth weight, pelvic inflammatory diseases, and increased susceptibility to HIV transmission.
In terms of diagnosis, wet preparation examination is only 60%-70% sensitive in women. Two point-of-care tests (OSOM Trichomonas Rapid Test and Affirm VP III) are available. These tests, performed on vaginal secretions, are more than 83% sensitive and more than 97% specific. Pap smears are not recommended for Trichomonas screening. In men, wet preparation of urethral discharge, prostatic secretions, or urethral scrapings is of uncertain sensitivity. Instead, PCR or culture on special media should be used.
Trichomoniasis is treated with metronidazole or tinidazole. If treatment with 2 g metronidazole given once fails (and reinfection is excluded), then patients should be treated with 500 g metronidazole twice daily for 7 days or with 2 g tinidazole once. If either therapy fails, then treat with 2 g metronidazole or 2 g tinidazole daily for 5 days. If this treatment fails, consult the CDC for testing and management. Sex partners of patients should be treated to prevent reinfection.
Metronidazole is pregnancy category B and tinidazole is pregnancy category C. Asymptomatic pregnant women should be counseled about the risks and benefits of treatment, Dr. Cantey noted.