A Sero‐Epidemiological Study on Mother‐to‐Child Transmission of HTLV‐I in Southern Kyushu, Japan*

Abstract

In vertical transmission of HTLV‐I the duration of breast‐feeding seems to be an important risk factor. In this study, we made prospective and retrospective surveys on the rate of vertical transmission of HTLV‐I in infants and their siblings born to HTLV‐I seropositive mothers. The results obtained were as follows. In the prospective study, 885 of the 16,283 pregnant women examined were HTLV‐I seropositive, and the seropositive rate was 5.4%. The seroconversion rates of short‐term (>7 months) and long‐term (≥7 months) breast‐feeders were 3.8% (1/ 26 cases) and 25.0% (1/4 cases) respectively, and the rate of bottle‐feeders was 5.6% (10/177 cases). Short‐term breast‐feeding tended to yield a lower seroconversion rate of infants. In addition, the seroconversion rate of short‐term breast‐feeders was nearly equal to that of bottle‐feeders: 3.8% vs. 5.6%. In the retrospective study, the seroconversion rates of short‐term and long‐term breast‐feeders in their siblings were 4.5% (3/67 cases) and 14.0% (19/136 cases) respectively. There was a significant difference between the 2 groups (P<0.01). Thus, the results of our retrospective and prospective studies suggest that short‐term breast‐feeding might lessen the risk of breast‐milk‐borne transmission of HTLV‐I from carrier mothers to their children.

Epidemiological Aspects and World Distribution of HTLV-1 Infection

“…Since the first studies, the repartition of HTLV-1 carriers in Japan is quite uneven with prevalence rates among blood donors varying from 1% in Hokkaido to more than 6% in Kyushu and Okinawa Islands in the Southern part of the archipelago (Hinuma et al, 1982; Maeda et al, 1984; Tajima, 1990). Several studies in pregnant women also revealed such a heterogeneous situation, which origin remains to be determined, with an HTLV-1 prevalence ranging from 0.5% (in North/central Japan) to 5.8% (Southern part of the country; Oki et al, 1992; Umemoto et al, 1994; Goto et al, 1997; Maehama, 2004). In some villages or towns of highly endemic areas, HTLV-1 prevalence can reach 30–40% in adults, aged more than 50 years old (Kohakura et al, 1986; Tajima et al, 1987).…”

A case of Adult T-cell leukemia/lymphoma (ATL) with a survival of more than 13 years

“…The patient most probably acquired the infection through prolonged breast-feeding, since his mother was seropositive and he had no history of blood transfusion. It is known that HTLV-I vertical transmission is directly proportional to the time of breastfeeding [7]. In conclusion, this is a case of ATL in a young adult with distinct clinical and histological manifestations and a prolonged survival time.…”

The Prevalence of Human T-Cell lymphotropic Virus Type 1 in Pregnant Women and Their Newborns

“…They found, the transmission rate in breastfed neonates was 41% by PCR, and none of formula feeding neonates was positive [19]. In another study conducted by Toshitaka and colleagues in Japan, 16283 pregnant women were studied, and seropositive prevalence of HTLV1 in them was 5.4%, and serum change in their infants who were breastfed for less than 7 months was 3.8% and in formula-fed infants was 5.6% [20]. Sexual transmission is a significant source for acquisition of HTLV1 in adult, and overall 15–25% of children born to infected women become infected [21].…”