Abstract Background: Zika virus (ZIKV) is a mosquito-borne virus that is also transmitted sexually, however, the epidemiological relevance of ZIKV sexual transmission in endemic regions is unclear. Methods: We performed a household-based serosurvey in Northeast Brazil to evaluate the differential exposure to ZIKV and chikungunya virus (CHIKV) among households. Individuals who participated in our previous arboviral disease cohort (indexes) were re-contacted and enrolled, and their household members were newly enrolled. Results: The Relative Risk (RR) of sexual partners being ZIKV seropositive when living with a ZIKV-seropositive index participant was significantly higher, while this was not observed among non-sexual partners of the index. For CHIKV, both sexual and non-sexual partner household members living with a CHIKV-seropositive index had a significantly higher risk of being seropositive. In the non-index based dyadic and generalized linear mixed model analyses, the odds of sexual dyads having a concordant ZIKV PRNT result was significantly higher. We have also analyzed retrospective clinical data according to the participants' exposure to ZIKV and CHIKV. Conclusion: Our data suggest that ZIKV sexual transmission may be a key factor for the high ZIKV seroprevalence among households in endemic areas and raises important questions about differential disease from the two modes of transmission. Keywords: Zika; arbovirus; chikungunya; epidemiology; mosquito; sexual transmission.

3rd November 2020 • comment

Zika epidemic and microcephaly in Brazil: Challenges for access to health care and promotion in three epidemic areas

by Paulo Cesar Peiter, Rafael dos Santos Pereira, Martha Cristina Nunes Moreira, Marcos Nascimento, Maria de Fatima Lobato Tavares, Vivian da Cruz Franco, José Joaquin Carvajal Cortês, Daniel de Souza Campos, Christovam Barcellos

Since 2015 Brazil has experienced the social repercussions of the Zika virus epidemic, thus raising a debate about: difficulties of diagnosis; healthcare access for children with Zika Congenital Syndrome (ZCS); the search for benefits by affected families; social and gender inequalities; and a discussion on reproductive rights, among others. The objective of this article is to analyse access to specialized health services for the care of children born with ZCS in three North-eastern states of Brazil. This is an exploratory cross-sectional study which analyses recorded cases of microcephaly at the municipal level between 2015 and 2017. Most of the cases of ZCS were concentrated on the Northeast coast. Rio Grande do Norte and Paraiba had the highest incidence of microcephaly in the study period. The states of Bahia, Paraiba and Rio Grande do Norte were selected for their high incidence of microcephaly due to the Zika Virus. Socio-territorial vulnerability was stratified using access to microcephaly diagnosis and treatment indicators. The specialized care network was mapped according to State Health Secretaries Protocols. A threshold radius of 100 km was stablished as the maximum distance from municipalities centroids to specialised health care for children with microcephaly. Prenatal coverage was satisfactory in most of the study area, although availability of ultrasound equipment was uneven within states and health regions. Western Bahia had the lowest coverage of ultrasound equipment and lacked health rehabilitation services. ZCS's specialized health services were spread out over large areas, some of which were outside the affected patients' home municipalities, so displacements were expensive and very time consuming, representing an extra burden for the affected families. This study is the first to address accessibility of children with microcephaly to specialised health care services and points to the urgent need to expand coverage of these services in Brazil, especially in the northeastern states, which are most affected by the epidemic.

14th July 2020 • comment

Mapping the response to Zika, a public health emergency, demonstrated a clear pattern of the participation of countries in the scientific advances. The pattern of knowledge production found in this study represented varying country perspectives, research capacity and interests based first on their level of exposure to the epidemic and second on their financial positions regarding science.

12th March 2020 • comment
24th January 2020 • comment