Estimation of HTLV-1 vertical transmission cases in Brazil per annum

Abstract

BackgroundBrazil has at least 800,000 HTLV-1 infected individuals. HTLV-1 can be transmitted via sexual intercourse, contact with blood and from mother to child, mainly by breastfeeding. Treatments for the high morbidity/mortality associated diseases (ATL and HAM/TSP) are limited, therefore, infection prevention is of utmost importance. However, antenatal screening is not routinely performed in Brazil. A lack of data regarding the number of individuals infected via breastfeeding impairs the development of government policies. The objective is to estimate the number of HTLV-1 infections occurring annually due to mother to child transmission (MTCT) in Brazil, nationally and regionally.MethodologyTo estimate HTLV-1 MTCT in Brazil the following variables are modelled: number of births, prevalence of HTLV-1 infection in pregnant women, breastfeeding duration rate and transmission risk according to breastfeeding period. The number of cases of HAM/TSP and ATL attributable to MTCT are also estimated.Principal findingsIn 2008, there were 2,934,828 live births in Brazil. HTLV prevalence in pregnant women in Brazil ranges between 0.1–1.05% by region. An estimated 16,548 HTLV-1 infected women are pregnant each year. According to the breastfeeding pattern and HTLV-1 prevalence of each region there are an estimated 3,024 new cases of HTLV-1 infection due to MTCT annually of which 2,610 are preventable through infant feeding advice. These 3,024 transmissions will result in 120–604 cases of ATL and 8–272 of HAM/TSP. North-East region comprises the high number of MTCT cases, followed by South-East.Conclusions/significanceA high number of new HTLV-1 infections due to MTCT occur every year in Brazil. Antenatal screening and avoiding breastfeeding are essential to prevent subsequent development of HTLV-1-associated diseases.

Adult T‐cell leukaemia/lymphoma in Brazil: A rare disease or rarely diagnosed?

“…Expected ATL cases in Brazil and its regions estimated accounting for differences in HTLV-1 prevalence between Brazil's regions, age and gender. The prevalence in women at reproductive age was considered to be the same as pregnant women (Rosadas et al, 2018).…”

Pooling of sera for human T-cell lymphotropic virus (HTLV) screening in a time of increasing health care expenditure and limited resources

“…One of the means to achieve this goal is to know the real prevalence of the infection and associated diseases in the general population and in individuals who could acquire/transmit this infection more easily, such as individuals infected with other microorganisms that share routes of transmission with HTLV-1 8,9,19,20 and HTLV-1-infected mothers who could transmit the virus to their infants during breastfeeding 4,6,7 . In Brazil, the estimated number of HTLV-1-infected individuals, as well as individuals with HTLV-1-associated diseases, is high but misdiagnosed 1,4,5,[21][22][23][24] ; thus, we decided to search for strategies that could reduce the cost of HTLV screening in this country to help the Ministry of Health of Brazil to introduce the serology of HTLV-1/2 in health care programs, especially in the national HTLV antenatal screening program. Using two EIAs commonly employed in screening in public health laboratories in Brazil, we tested the strategy of pooling sera, taking into account previous studies that demonstrated that pooling is feasible and costeffective mostly in populations with low prevalence of HIV and HTLV and/or in countries with limited resources [12][13][14][15] .…”

“…Thus, we could suppose that the present pool of five sera using EIA Murex could also be employed in this population. Indeed, this strategy could be helpful for extending the HTLV diagnosis, since: (i) the number of HAM/TSP and ATL cases due to HTLV-1 mother-to-child transmission in Brazil has been underestimated 21,22 , (ii) the low number of HAM/TSP and ATLL cases described in this country could be due to the lack of or misdiagnosis rather than to the low incidence, (iii) the complexity of clinical manifestation and laboratory diagnosis of both diseases, (iv) the lack of knowledge in HTLV-1 and associated diseases among health professionals, (v) the difficult access to public health care in Brazil, especially in low-income areas, and (vi) the high morbidity/mortality of diseases [21][22][23][24] .…”

A Nationwide Antenatal Human T-Cell Leukemia Virus Type-1 Antibody Screening in Japan

“…As children with longer duration of breastfeeding have higher rates of MTCT (Rosadas et al, 2018), it should be noted that MTCT rate in the longer-term breastfeeding group depends on the distribution of breastfeeding duration in the included subjects.…”

“…In turn, the prevalence of HTLV-1-associated diseases could be reduced, and the rising trend in the number of people with horizontal infection could be curbed to some extent. Non-endemic and endemic countries may have different views on the need to introduce a nationwide screening program, but in countries or areas where HTLV-1 is endemic, antenatal screening is likely to contribute to a reduction in the burden of associated diseases (Ribeiro et al, 2012;Rosadas et al, 2018).…”