5 research outputs found
Discovery of Markers of Exposure Specific to Bites of Lutzomyia longipalpis, the Vector of Leishmania infantum chagasi in Latin America
Leishmania parasites are transmitted by the bite of an infected vector sand fly that injects salivary molecules into the host skin during feeding. Certain salivary molecules can produce antibodies and can be used as an indicator of exposure to a vector sand fly and potentially the disease it transmits. Here we identified potential markers of specific exposure to the sand fly Lutzomyia longipalpis, the vector of visceral leishmaniasis in Latin America. Initially, we determined which of the salivary proteins produce antibodies in humans, dogs, and foxes from areas endemic for the disease. To identify potential specific markers of vector exposure, we produced nine different recombinant salivary proteins from Lu. longipalpis and tested for their recognition by individuals exposed to another human-biting sand fly, Lu. intermedia, that transmits cutaneous leishmaniasis and commonly occurs in the same endemic areas as Lu. longipalpis. Two of the nine salivary proteins were recognized only by humans exposed to Lu. longipalpis, suggesting they are immunogenic proteins and may be useful in epidemiological studies. The identification of specific salivary proteins as potential markers of exposure to vector sand flies will increase our understanding of vector–human interaction, bring new insights to vector control, and in some instances act as an indicator for risk of acquiring disease
Pertussis vaccine effectiveness following country-wide implementation of a hexavalent acellular pertussis immunization schedule in infants and children in Panama
Despite high pediatric vaccination coverage rates (VCRs), pertussis incidence has increased worldwide, including in several countries in Latin America in the last two decades. Given the few vaccine effectiveness (VE) studies in Latin American countries, this retrospective, observational, cohort study estimated the effectiveness of hexavalent acellular (aP) primary and booster vaccination (wP) against pertussis in infants (6.5–18.5 months) and children (18.5–48.5 and 48.5–72.5 months) in Panama. Age-specific incidence rates (IRs) were calculated for the vaccine’s pre-initiation (2001–2013), initiation (2014), and post-initiation (2015–2019) periods. VCRs and trends were determined, and VE was analyzed using a case coverage or screening method to compare proportions of vaccinated cases and vaccinated individuals in the population. Between 2001–2019, 868 confirmed pertussis cases were reported in Panama; 712 (82.0%; 54.8 cases/year) during the pre-initiation period, 19 (2.2%; 19 cases/year) during the initiation period, and 137 (15.8%; 27.4 cases/year) during the post-initiation period. Panama underwent cyclical increases in IRs, which varied between age groups. VCRs increased for primary and booster doses. Between 2015 and 2019, third-dose yearly vaccine coverage increased, on average, 3.3%. Specifically, during the post-initiation period, 109/137 (79.6%) of cases were unvaccinated. Relative VE was estimated at 96.2% [95% CI: 86.5%, 98.9%] with three doses; 100% with 4 and 5 booster doses. Absolute VE was estimated at 99.3% with three doses only. These results show that vaccination played an important role in maintaining a low number of pertussis cases in Panama, affirming the need for sustained investment and commitment to vaccination programs