First Case of Human Ehrlichiosis in Mexico.To the Editor: Ehrlichiosis is a zoonotic disease transmitted to humans through the bite of infected ticks (1). The first recognized human ehrlichial infection, Sennetsu fever, was described in Japan in 1954 (2). The first case of human ehrlichiosis in the United States was recognized in 1986 and was reported in 1987 (3). The disease is caused by intracellular gram-negative bacteria of the Ehrlichia genus. The bacteria can be found in the monocytes monocytes, n.pl the largest of the white blood cells. They have one nucleus and a large amount of grayish-blue cytoplasm. Develop into macrophages and both consume foreign material and alert T cells to its presence. and granulocytes Granulocytes White blood cells. Mentioned in: Blood Donation and Registry granulocytes (granˑ·y of peripheral blood. Human monocytic ehrlichiosis human monocytic ehrlichiosis Infectious disease An infection by Ehrlichia chaffeensis Vector Lone Star tick–Amblyomma americanum, possibly also Dermacentor variabilis is caused by E. chafeensis, and human granulocytic ehrlichiosis human granulocytic ehrlichiosis: see ehrlichiosis. is caused by E. equi or E. phagocytophilia, which was first recognized in 1994 (4). Most cases occur between April and September, and the reservoirs are field animals such as rodents, deer, and dogs. The clinical spectrum of the disease is similar to that of other febrile illnesses; without adequate and timely treatment, approximately 5% of the patients die (5). In the United States, more than 400 cases of serologically confirmed E. chaffensis infection have been documented since 1996 (6). No cases have been reported in Mexico. In February 1997, we evaluated a 41-year-old male patient from Merida. The patient had been exposed to ticks during activity in a rural area 1 week before the onset of illness. Clinical manifestations included frequent hyperthermia hyperthermia /hy·per·ther·mia/ (-ther´me-ah) hyperpyrexia; greatly increased body temperature.hyperther´malhyperther´mic malignant hyperthermia , rash, myalgia, headache, anorexia, fatigue, and cough. Physical examination showed bilateral cervical lymphadenopathy, and a chest radiograph showed an interstitial bilateral infiltrate. Hematic cytometry showed thrombocytopenia of 134 x [10.sup.3] [micro]L and 3200 leukocytes (1440 neutrophils/[micro]L). Hepatic transaminases were elevated, with an aspartate aminotransferase: 92 U/L (normal: 22 U/L), alanine aminotransferase: 48 U/L (normal: 18 U/L), gamma-glutamyltranspeptidase: 278 U/L (normal: 28 U/L); and globulins Globulins A group of proteins in blood plasma whose levels can be measured by electrophoresis in order to diagnose or monitor a variety of serious illnesses. Mentioned in: Protein Electrophoresis : 4.8 g/dL with a polyclonal pattern. No antibodies against rickettsia rickettsia (rĭkĕt`sēə), any of a group of very small microorganisms, many disease-causing, that live in vertebrates and are transmitted by bloodsucking parasitic arthropods such as fleas, lice (see louse), and ticks. , dengue virus, B-19 parvovirus parvovirus (pär'vōvī`rəs), any of several small DNA viruses that cause several diseases in animals, including humans. In humans, parvoviruses cause fifth disease, or erythema infectiosum, an acute disease usually affecting young , or HIV HIV (Human Immunodeficiency Virus), either of two closely related retroviruses that invade T-helper lymphocytes and are responsible for AIDS. There are two types of HIV: HIV-1 and HIV-2. HIV-1 is responsible for the vast majority of AIDS in the United States. were detected. A serum sample gave a positive reaction by indirect immunofluorescence assay against E. chaffeensis at titers of 1:64 on week 2 and 1:128 on week 3. No infected monocytes or granulocytes were observed in peripheral blood. Remission of the clinical manifestations began on week 4 and was completed on week 6. This case indicates the existence of human ehrlichiosis in Yucatan, Mexico. Reactivity to E. chaffeensis suggests human monocytic ehrlichiosis; however, as antibody testing was not performed with E. phagocytophila or E. equi, the possibility of human granulocytic ehrlichiosis cannot be excluded. In any event, case reports indicate the need for deliberate search for cases. Dengue is endemic in this area of Mexico, and ehrlichiosis should be considered as a differential diagnosis. References (1.) Dumler SJ, Bakken JS. Ehrlichial diseases of humans: emerging tick-borne infections. Clin Infect Dis 1995;20:1102-10. (2.) Schaffner W, Standaert SM. Ehrlichiosis--in pursuit of an emerging infection. N Engl J Med 1996;334:262-3. (3.) Maeda K, Markowitz N, Hawley RC, Ristic M, Cox D, McDade JE. Human infection with Ehrlichia canis, a leucocytic rickettsia. N Engl J Med 1987;316:853-6. (4.) Bakken JS, Dumler JS, Chen SM, Eckman MR, Van Etta LL, Walker DH. Human granulocytic ehrlichiosis in the upper midwest United States: a new species emerging? JAMA JAMA abbr. Journal of the American Medical Association 1994;272:212-8. (5.) Walker D, Raoult D, Brouqui P, Marrie T. Rickettsial diseases. In: Fauci AS, Braunwald E, Isselbacher KJ, Wilson JD, Martin JB, Kasper DL, et al., editors. Harrison's principles of internal medicine Harrison's Principles of Internal Medicine is an American textbook of internal medicine. First published in 1950, it is presently in its sixteenth edition. Although it is aimed at all members of the medical profession, it is mainly used by internists and junior doctors in . 14th ed. New York: The McGraw-Hill Companies; 1998. p. 1045-52. (6.) Walker DH, Dumler JS. Emergence of the ehrlichioses as human health problems. Emerg Infect Dis 1996;2:18-29. Renan A. Gongora-Biachi,(*) Jorge Zavala-Velazquez,([dagger]) Carlos Jose Castro-Sansores,(*) and Pedro Gonzilez-Martinez(*) (*) Centro de Investigaciones Regionales "Dr. Hideyo Noguchi," Merida, Yucatan, Mexico; and ([dagger] Facultad de Medicina, Universidad Autonoma de Yucatan, Merida, Yucatan, Mexico |
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