Natural Vertical Transmission of Dengue Virus Serotype 4 in Aedes aegypti Larvae from Urban Areas in Sinaloa, Mexico.

Dengue virus (DENV) is transmitted to humans by the bite of the vector Aedes aegypti. Several researchers have suggested that the mechanism of vertical transmission of DENV in the vector is a key aspect for the prevalence of the virus in the environment and the potentiation of epidemic outbreaks of the disease. In this context and as part of an integrated study of DENV serotypes in mosquitoes of urban areas in Sinaloa, Mexico, the presence of DENV-4 in larval stages of Ae. aegypti was evaluated to demonstrate the vertical transmission of this serotype. In total, 672 larvae of Ae. aegypti were collected in 16 sectors and were grouped into 36 pools, of which 41.66% (15/36 pools) tested positive for DENV-4, with a minimum infection rate = 22.32. The analysis of the obtained sequences showed a 98% similarity to the DENV-4 with sequences previously reported in GenBank. These results show that Ae. aegypti acts as a natural reservoir for DENV-4 in this region.

Immunoproteomic Identification of p29 Antigen as the Elongation Factor-1α of Leishmania mexicana.

Previously, we identified five Leishmania mexicana antigens reacting with antibodies from cutaneous leishmaniasis patients, designated on the basis of their molecular weights as p26 (pI 7.8), p27 (pI 8.1), p28 (pI 8.6), p29 (pI 8.5), and p31 (pI 9.0). Among these antigens, p29 was most strongly recognized by the antibodies. Thereafter, p29 was identified as elongation factor-1α (EF-1α) of Leishmania mexicana through mass spectrometry analysis and western blot using a commercial antibody that reacted with EF-1α from different species. Our results showed that the p29 antigen of Leishmania mexicana is EF-1α.

First Record of Aedes albopictus in Sinaloa, Mexico.

We report here the discovery of Aedes albopictus for the first time in Sinaloa state, Mexico. The mosquito larvae were collected from small water containers in the urban area of Culiacan city, Sinaloa state. Identification of the species was done primarily by morphology, followed by confirmation with polymerase-chain-reaction-based molecular method.

Molecular diagnosis of Leishmania mexicana in a cutaneous leishmaniasis case in Sinaloa, Mexico.

Leishmaniasis has been considered endemic in Sinaloa, Mexico, since 1994. Despite that Leishmania mexicana is the main etiological agent of cutaneous leishmaniasis (CL) in other regions of Mexico, the species causing CL in patients from Sinaloa state has not been previously established, although Leishmania braziliensis has been found in the neighboring southern state, Nayarit. L. braziliensis is also associated with mucocutaneous leishmaniasis, which is a more complicated clinical variant. Due to the implications on individual and public health, the objective of this report was to identify the Leishmania species present in Sinaloa, Mexico. Using the first internal transcribed spacer (ITS-1) polymerase chain reaction-restriction fragment length polymorphism, we identified L. mexicana in a CL patient from Sinaloa and confirmed the extended distribution of this parasite in Mexico.