Epidemiology

HTLV-1

Related diseases

Two diseases has been definitely linked to the HTLV-I: Adult T cells leukemia/lymphoma (ATL) and a chronic degenerative neurological quadro , tropical spastic paraparesis/myelopathy linked to the HTLV-I (HAM/TSP). ATL is a malignity of the CD4+ T Lymphocytes infected by the HTLV-I. The HTLV-I provirus is monoclonally integrated on abnormal cells population. A large clinical spectrum was described as pathological characteristic, including acute, chronic, lymphomatosis, and light forms (36, 37). The TL acute form is characterized by lymphonodes, viscera, and skin infiltration with malign cells, resulting in a variety of clinical characteristics (Table 2). Abnormal circulating lymphocytes, cells in a flower form, generally are observed. Hypercalcemia, abnormal hepatic enzymes, and lytic lesions on the bones are common. The average survival is 11 months after the diagnosis. Conventional chemotherapy is not curable, and recurrence happens frequently and rapidly, although extended survival has been noticed. ATL was calculated to occur in 2%-4% of people in the regions where HTLV-I is endemic, and where precocious infection in childhood is common (38,39). ATL occurs with frequency among people with 40-60 years of age, suggesting latency period of some decades to develop the disease. One case of ATL was reported in an immunocompromised patient, with whom the infection seems to havebeen acquired through transfusion (40). HAM/TSP is characterized by the progressive loss of strength in the lower body ; steady, with spasticity, hyperreflexia, sensorial disturbances, and urinary incontinence (Table 2). In patients with HAM/TSP, contrary to those with multiple sclerosis, the signs and symptoms are progressive, the cranial nerves are not involved, and the cognitive function is not affected. Anti-HTLV-I antibodies are found in the cerebrospinal fluid (41). Treatment with corticosteroids was reported as useful in some cases (42). Danazol, a synthetic androgen, help to improve the symptoms according reports, including organic deficiency of the vesical function (42,44), and more recently the use of interferon-2-alpha has obtained good results ( ) . HAM/TSP is developed in less than 1% of the people with HTLV-I (45). It is considered as immunologically mediated , frequently affecting more women than men. Latency period for HAM/TSP is shorter than the ATL; cases of HAM/TSP were associated with blood transfusion, with an interval rate at 3.3 years between transfusion and the development of HAM/TSP (46). Recently, infectious dermatitis, a chronic eczema associated to Staphylococcus aureus and to the beta-hemolytic streptococcus, was observed in Jamaican children infected with the HTLV-I (47). The spectrum of diseases associated to HTLV-I could include other disorders. Cases of polymyositis (48), chronic arthropathy (49), pan-bronchitis (50), and uveitis (51) were reported in patients infected with the HTLV-I.