Dengue y otras fiebres hemorrágicas virales

[Could malaria and dengue reappear in Spain?]

The recent increase in immigration to Spain has facilitated the importation of many tropical diseases. Among these diseases, those of vectorial origin are among the most difficult to study. Some of the reasons for this difficulty are the complexity due to the variety of hosts involved in the transmission cycles and the need to know all the physiological, bioecological and biogeographic parameters related to the vector in order to infer the actual possibilities of the emergence or reemergence of these diseases. This article provides information on imported diseases of unquestionable epidemiological interest for the population in Spain due to the presence of several species of culicid mosquitoes (Diptera, Culicidae) capable of transmitting these diseases in our country. Parasitic diseases such as malaria, which was highly endemic in Spain until 50 years ago, and other arboviral infections such as dengue and yellow fever, are analyzed in these terms. Various aspects related to the health system, as well as the different ways of tackling these issues, are also discussed.

Evidence of vertical transmission of dengue virus in two endemic localities in the state of Oaxaca, Mexico

BACKGROUND

Dengue virus is spread in tropical areas of the world and is the causative agent of dengue fever and dengue hemorrhagic fever. It is horizontally transmitted to humans by infected Aedes mosquitoes, but it is also able to be vertically or transovarially transmitted to insect progeny.

OBJECTIVE

In this work, we analyzed the vertical transmission of dengue virus in Aedes aegypti mosquitoes collected in two endemic localities in the state of Oaxaca, Mexico.

METHODS

The collected larvae were grown in the laboratory and transovarial transmission of dengue virus, either in larvae or newly emerged mosquitoes, was investigated using a semi-nested reverse transcription-polymerase chain reaction method.

RESULTS

Although the presence of dengue virus in larvae could not be demonstrated, the viral genome was amplified in 4 out of 43 pools of in-cage born mosquitoes: DEN 2, 3 and 4 serotypes were detected in 2 pools from Tuxtepec and two from Juchitán.

CONCLUSION

The results presented here strongly suggest that dengue virus can be vertically transmitted in mosquitoes from Oaxaca, but more studies will be necessary to analyze the epidemiological impact of this mechanism of transmission.