Acute Schistosomiasis – Continued S. mansoni eggs per gram of stool; no other helminthic or protozoal pathogens were observed. Serologic tests for antibody to mycoplasma, Epstein Barr virus (EBV), and other viral agents were negative. On May 15, the patient was transferred to a spinal cord rehabilitation center. His neurologic condition remains unchanged. Student 2: A 20-year-old white female was in good health and had not previously traveled overseas. She received similar immunizations as Student 1 and took chloroquine and Fansidar® weekly for malaria prophylaxis. On April 29, she developed fever, abdominal pain, and nonbloody diarrhea. A Gram stain of her urine showed gram-positive cocci, and she was treated with ampicillin. She also received metronidazole, although it was unclear whether amoebae were found by stool examination. On May 3, she developed severe back pain without radiation, weakness, or urinary symptoms. From May 7 to May 9, she rapidly lost the ability to ambulate. She complained of difficulty initiating her urine stream. On May 9, after a stool examination showed many ova of S. mansoni, she was diagnosed as having schistosomal transverse myelitis and treated with oxamniquine. She was transported to the United States on May 11. Evaluation in the United States was unremarkable except for a flaccid paralysis and severely decreased sensation to temperature and touch in the lower extremities. Deep tendon reflexes could not be elicited. The level of the lesion was placed at L1-L2. There was moderate eosinophilia. CSF examination showed pleocytosis and elevated protein; however, eosinophilic pleocytosis was not present. A myelogram showed no obstruction, but a CAT scan of the spine suggested some swelling of the conus medullaris. Stool examination showed only S. mansoni (1,100 eggs per gram of feces). Serologic tests for antibody to mycoplasma, EBV, and other viral agents were negative. Because the dose of oxamniquine given in Kenya was considered inadequate, the patient was treated with praziquantel. Large doses of dexamethasone were also given. The patient's motor function and sensation improved by the second treatment day. On May 15, she began moving both extremities against gravity. On June 8, the patient was ambulating with assistance at a spinal rehabilitation center. Reported by J Houpis, MD, Brattleboro, Vermont; J Oexmann, MD, J Martin, MD, G Jacobi, MD, Depts of Neurology and Infectious Diseases, Massachusetts General Hospital, Boston; J Reardon, MD, Assistant Director, Div of Communicable and Venereal Diseases, G Waterman, MD, Acting State Epidemiologist, Massachusetts Dept of Health; Helminthic Diseases Br, Div of Parasitic Diseases, Center for Infectious Diseases, CDC. Editorial Note: Although S. mansoni and S. haematobium are endemic to the Machakos district of Kenya (1), no infections with S. haematobium occurred among any of the 18 students. Schistosomiasis of the central nervous system (CNS) was first recognized in the late 19th century and has been most commonly reported as a cerebral granulomatous disease resulting from ectopically located S. japonicum eggs (2). Schistosomal transverse myelitis is rare and has been observed most frequently in infections with S. mansoni (3). Since S. mansoni transverse myelitis (SMTM) was first reported in 1930, about 32 tissue-proven cases and over 28 presumed cases have been reported. When autopsy or surgical biopsy is not performed, a presumptive diagnosis of SMTM is based on the following considerations: (1) the finding of low thoracic/upper lumbar neurological symptoms; (2) demonstration of exposure to schistosomes through parasitologic or serologic techniques; and (3) the exclusion of other known causes of transverse myelitis (5,6). In contrast to schistosomal transverse myelitis, other causes of transverse myelitis commonly affect the mid-thoracic cord (4). Eosinophilic pleocytosis in the CSF is suggestive of schistosomiasis of the CNS but is often not observed, as in the cases reported here. Other disorders that have been associated with transverse myelitis include numerous viral, bacterial, and fungal infections (especially with enterovirus, EBV, tuberculosis, syphilis, and coccidioidomycosis), postvaccinal reactions, collagen vascular diseases, toxin exposures, and vascular disease. Conditions that can mimic transverse myelitis include tumor, Guillan-Barré syndrome, and multiple sclerosis (4). All of these, including SMTM, are rare, and the observed attack rate of 13% (2/15) in this group of students is unusual, regardless of etiology. Schistosomal myelopathy results from the inflammatory reaction accompanying the deposition of eggs in the venules located in and around the spinal cord (2,3). How eggs, which are normally oviposited in the venules of the inferior mesenteric vein of the portal system, reach the spinal vascular system is unknown. Several hypotheses have been proposed (2,3,6). Praziquantel or oxamniquine are the antischistosomal agents available to treat SMTM. Treatment destroys the adult worms and thereby prevents further oviposition. Praziquantel is effective against all schistosomes; however, oxamniquine is only effective against S. mansoni. The dosage of oxamniquine needed varies according to the geographic location where the infection was acquired (7). Steroids are used to suppress the host response around the ectopic eggs (5,6). Myelography may identify discrete granulomatous masses that may be amenable to surgical removal (8). In 50% of reported cases, there is little or no return of neurologic function (2,3,5,6), and intensive rehabilitative care is indicated. When evaluating persons for infection with schistosomes, interpretation of negative tests may be difficult, since extremely mild infections or ectopic localization of worms may preclude detection of eggs with stool or urine examinations. Because of the potential benefit of the recommended therapy, presumptive treatment of patients with diagnoses of transverse myelitis and histories of water exposure in endemic areas should be initiated while awaiting results of parasitologic or serologic tests. The severity of illness in this group should reemphasize the need for travelers visiting areas endemic for schistosomiasis to be aware of precautions that may decrease the risk of infection. Since there is no practicable way to distinguish infested from noninfested water, it is prudent to avoid fresh-water swimming. Heating bathing water to 50 C (122 F) for 5 minutes or treating it with iodine or chlorine in a manner similar to the precautions recommended for preparing drinking water will destroy cercaria. Filtering water with a tightly woven cloth or with paper coffee filters may also be effective in removing cercaria from bathing water. If these measures are not feasible, allowing bathing water to stand for 3 days is advisable, since cercaria survive only 48 hours. If accidental exposure to suspected water occurs, immediate and vigorous towel drying or rapid application of rubbing alcohol to the exposed areas may reduce the risk of infection. The effectiveness of available antischistosomal drugs as chemoprophylactic agents has not been evaluated (9). References 1. Arap Siongok TK, Mahmoud AAF, Ouma JH, et al. Morbidity in Schistosomiasis mansoni in relation to intensity of infection: study of a community in Machakos, Kenya. Am J Trop Med and Hyg 1976; 25:273-84. 2. Faust EC. Inquiry into ectopic lesions in schistosomiasis. Am J Trop Med Hyg 1948, 28:175-99. 3. Marcial-Rojas RA, Fiol RE. Neurologic complications of schistosomiasis. Review of the literature and report of two cases of transverse meyelitis due to S. mansoni. Ann Intern Med 1963;59:215-30. 4. Wyngaarden JB, Smith LH, eds. In: Cecil-Loeb textbook of medicine, 16th ed. Philadelphia: WB Saunders, 1982:2106-8. 5. Neves J, Marinho RP, De Araujo PK, Raso P. Spinal cord complications of acute Schistosomiasis mansoni. Transactions Royal Society Trop Med Hyg 1973;67:782-92. 6. Lechtenberg R, Vaida GA. Schistosomiasis of the spinal cord. Neurology 1977;27:55-9. 7. The Medical Letter. Drugs for parasitic infections. The Medical Letter 1984:26;27-32. 8. Cohen J, Capildeo R, Rose FC, et al. Schistosomal myelopathy. Br Med J 1977;1:1258. 9. Istre G, Fontaine RE, Tarr J, et. al. Acute schistosomiasis among Americans rafting the Omo River, Ethiopia. JAMA 1984;251:508-10. Work-Related Allergies in Insect-Raising Facilities Complaints of skin and respiratory allergies have frequently been reported by employees in facilities that raise insects for entomologic research. In 1980, the U.S. Department of Agriculture asked the National Institute for Occupational Safety and Health (NIOSH) to conduct a health hazard evaluation among employees of the Agricultural Research Service (ARS). For this study, NIOSH used a mailed, self-administered questionnaire. This questionnaire was designed to assess the prevalence of symptoms possibly related to allergenic airborne particulates associated with raising colonies of insects in confined spaces; the frequency of insect bites or stings was not of major concern in the study. The following case reports are representative of those elicited by the survey. Case 1: A worker had onset of burning eyes and nasal and sinus "stuffiness" after working for about 2 years with various moth species. These symptoms typically began approximately an hour after exposure to the moths and would last up to 1 day after exposure ceased. Use of (Continued on page 453) TABLE 1. Summary-cases specified notifiable diseases, United States 'Two of the 46 reported cases for this week were imported from a foreign country or can be directly traceable to a known internationally imported case within two generations. |