Vertical Transmission of Zika Virus (Flaviviridae, Flavivirus) in Amazonian Aedes aegypti (Diptera: Culicidae) delays egg hatching and larval development of progeny.

Zika virus (ZIKV) has emerged as a globally important arbovirus and has been reported from all states of Brazil. The virus is primarily transmitted to humans through the bite of an infective Aedes aegypti (Linnaeus, 1762) or Aedes albopictus (Skuse, 1895). However, it is important to know if ZIKV transmission also occurs from Ae. aegypti through infected eggs to her offspring. Therefore, a ZIKV and dengue virus (DENV) free colony was established from eggs collected in Manaus and maintained until the third?fourth generation in order to conduct ZIKV vertical transmission (VT) experiments which used an infectious bloodmeal as the route of virus exposure. The eggs from ZIKV-infected females were allowed to hatch. The resulting F1 progeny (larvae, pupae, and adults) were quantitative polymerase chain reaction (qPCR) assayed for ZIKV. The viability of ZIKV vertically transmitted to F1 progeny was evaluated by cultivation in C6/36 cells. The effects of ZIKV on immature development of Ae. aegypti was assessed and compared with noninfected mosquitoes. Amazonian Ae. Aegypti were highly susceptible to ZIKV infection (96.7%), and viable virus passed to their progeny via VT. Moreover, eggs from the ZIKV-infected mosquitoes had a significantly lower hatch rate and the slowest hatching. In addition, the larval development period was slower when compared to noninfected, control mosquitoes. This is the first study to illustrate VT initiated by oral infection of the parental population by using mosquitoes, which originated from the field and a ZIKV strain that is naturally circulating in-country. Additionally, this study suggests that ZIKV present in the Ae. aegypti can modify the mosquito life cycle. The data reported here suggest that VT of ZIKV to progeny from naturally infected females may have a critical epidemiological role in the dissemination and maintenance of the virus circulating in the vector

Saliva of laboratory-reared Lutzomyia longipalpis exacerbates Leishmania (Leishmania) amazonensis infection more potently than saliva of wild-caught Lutzomyia longipalpis

In order to compare the saliva effect from wild-caught and lab-reared L. longipalpis on the development of experimental cutaneous leishmaniasis, C57BL/6 mice were inoculated subcutaneously into the hind footpads with promastigotes of L (L.) amazonensis Plus salivary gland lysate from wild-caught (SGL-W) and lab-colonized (SGL-C) vectors. Lesion sizes were significantly larger in the mice infected with both saliva compared to mice infected with parasites alone; moreover, the lesions caused by parasite+SGL-C were significantly larger than the lesions caused by parasite+SGL-W. Histopathological morphometric studies regarding the acute phase of infections showed lower numbers of polymorphonuclear cells, greater numbers of mononuclear cells and parasites in SGL-C infected mice compared to SGL-W infected mice. In the chronic phase of infection, the number of mononuclear cells was lower and the number of parasites was greater in SGL-C infected mice than SGL-W infected mice. In vitro studies showed increased infection index of macrophages infected with parasites plus saliva compared to infection with parasites alone, with no difference between the saliva infection indices. SDS-PAGE gel for SGL-C and SGL-W showed differences in the composition and quantity of protein bands, determined by densitometry. These results call attention to the experimental saliva model, which shows exacerbation of infection caused by sandfly saliva. (C) 2009 Elsevier Ireland Ltd. All rights reserved

Studies on the influence of the presence of domestic animals on increasing the transmission probalities of Leishmaniasis

Submitted by Ana Maria Fiscina Sampaio ([email protected]) on 2016-09-27T16:15:25Z No. of bitstreams: 1 Miranda Studies of the influence....pdf: 1521988 bytes, checksum: ac564f139f61b270b2265fc4f69cc798 (MD5)Approved for entry into archive by Ana Maria Fiscina Sampaio ([email protected]) on 2016-09-27T16:54:00Z (GMT) No. of bitstreams: 1 Miranda Studies of the influence....pdf: 1521988 bytes, checksum: ac564f139f61b270b2265fc4f69cc798 (MD5)Made available in DSpace on 2016-09-27T16:54:00Z (GMT). No. of bitstreams: 1 Miranda Studies of the influence....pdf: 1521988 bytes, checksum: ac564f139f61b270b2265fc4f69cc798 (MD5) Previous issue date: 2008CNPq. FAPEMIG-PRONEX. FIOCRUZFundação Oswaldo Cruz. Instituto de Pesquisas Gonçalo Moniz. Laboratório de Imunoparasitologia. Salvador, BA, BrasilFundação Oswaldo Cruz. Instituto de Pesquisas René Rachou. Laboratório de Entomoloiga Médica. Belo Horizonte, MG, BrasilFundação Oswaldo Cruz. Instituto de Pesquisas René Rachou. Laboratório de Entomoloiga Médica. Belo Horizonte, MG, BrasilFundação Oswaldo Cruz. Instituto de Pesquisas Gonçalo Moniz. Laboratório de Imunoparasitologia. Salvador, BA, BrasilFundação Oswaldo Cruz. Instituto de Pesquisas Gonçalo Moniz. Laboratório de Imunoparasitologia. Salvador, BA, BrasilFundação Oswaldo Cruz. Instituto de Pesquisas Gonçalo Moniz. Laboratório de Imunoparasitologia. Salvador, BA, BrasilFundação Oswaldo Cruz. Instituto de Pesquisas Gonçalo Moniz. Laboratório de Imunoparasitologia. Salvador, BA, BrasilFundação Oswaldo Cruz. Instituto de Pesquisas Gonçalo Moniz. Laboratório de Imunoparasitologia. Salvador, BA, BrasilFundação Oswaldo Cruz. Instituto de Pesquisas René Rachou. Laboratório de Entomoloiga Médica. Belo Horizonte, MG, BrasilFundação Oswaldo Cruz. Instituto de Pesquisas Gonçalo Moniz. Laboratório de Imunoparasitologia. Salvador, BA, BrasilFundação Oswaldo Cruz. Instituto de Pesquisas René Rachou. Laboratório de Entomoloiga Médica. Belo Horizonte, MG, BrasilIn the endemic regions of leishmaniasis in tropical countries, a great majority of poor residentes of rural áreas, keep a variety of domestic animals for socioeconomic and other reasons. The vector sandflies feed several times on diferente animals. It was found that feeding on certain healthy domestic animals may potentially increase the transmission powers of parasite Leishmania carrying vectors. The conclusion is based on the observation that in áreas where these animals were kept, sandflies were more numerous, and carried a larger parasite load. The occurrence of such a phenomenon provides a selective advantage to the transmission of Leishmania among vertebrates. These results may enable the health authorities to adopt policies concerning the presence of domestic animals in endemic áreas which result in significant reduction in the numbers of Leishmania cases in the human beings in these áreas

Zika virus transmission to mouse ear by mosquito bite: a laboratory model that replicates the natural transmission process

Abstract Background Zika disease has transformed into a serious global health problem due to the rapid spread of the arbovirus and alarming severity including congenital complications, microcephaly and Guillain-Barré syndrome. Zika virus (ZIKV) is primarily transmitted to humans through the bite of an infective mosquito, with Aedes aegypti being the main vector. Methods We successfully developed a ZIKV experimental transmission model by single infectious Ae. aegypti bite to a laboratory mouse using circulating Brazilian strains of both arbovirus and vector. Mosquitoes were orally infected and single Ae. aegypti were allowed to feed on mouse ears 14 days post-infection. Additionally, salivary gland (SG) homogenates from infected mosquitoes were intrathoracically inoculated into naïve Ae. aegypti. Mosquito and mouse tissue samples were cultured in C6/36 cells and processed by quantitative real-time PCR. Results A total of 26 Ae. aegypti were allowed to feed individually on mouse ears. Of these, 17 mosquitoes fed, all to full engorgement. The transmission rate of ZIKV by bite from these engorged mosquitoes to mouse ears was 100%. The amount of virus inoculated into the ears by bites ranged from 2 × 102–2.1 × 1010 ZIKV cDNA copies and was positively correlated with ZIKV cDNA quantified from SGs dissected from mosquitoes post-feeding. Replicating ZIKV was confirmed in macerated SGs (2.45 × 107 cDNA copies), mouse ear tissue (1.15 × 103 cDNA copies, and mosquitoes 14 days post-intrathoracic inoculation (1.49 × 107 cDNA copies) by cytopathic effect in C6/36 cell culture and qPCR. Conclusions Our model illustrates successful transmission of ZIKV by an infectious mosquito bite to a live vertebrate host. This approach offers a comprehensive tool for evaluating the development of infection in and transmission from mosquitoes, and the vertebrate-ZIKV interaction and progression of infection following a natural transmission process

The role of the peritrophic matrix and red blood cell concentration in Plasmodium vivax infection of Anopheles aquasalis

Abstract Background Plasmodium vivax is predominant in the Amazon region, and enhanced knowledge of its development inside a natural vector, Anopheles aquasalis, is critical for future strategies aimed at blocking parasite development. The peritrophic matrix (PM), a chitinous layer produced by the mosquito midgut in response to blood ingestion, is a protective barrier against pathogens. Plasmodium can only complete its life-cycle, and consequently be transmitted to a new host, after successfully passing this barrier. Interestingly, fully engorged mosquitoes that had a complete blood meal form a thicker, well-developed PM than ones that feed in small amounts. The amount of red blood cells (RBC) in the blood meal directly influences the production of digestive enzymes and can protect parasites from being killed during the meal digestion. A specific study interrupting the development of the PM associated with the proteolytic activity inhibition, and distinct RBC concentrations, during the P. vivax infection of the New World malaria vector An. aquasalis is expected to clarify whether these factors affect the parasite development. Results Absence of PM in the vector caused a significant reduction in P. vivax infection. However, the association of chitinase with trypsin inhibitor restored infection rates to those of mosquitoes with a structured PM. Also, only the ingestion of trypsin inhibitor by non-chitinase treated mosquitoes increased the infection intensity. Moreover, the RBC concentration in the infected P. vivax blood meal directly influenced the infection rate and its intensity. A straight correlation was observed between RBC concentrations and infection intensity. Conclusions This study established that there is a balance between the PM role, RBC concentration and digestive enzyme activity influencing the establishment and development of P. vivax infection inside An. aquasalis. Our results indicate that the absence of PM in the midgut facilitates digestive enzyme dispersion throughout the blood meal, causing direct damage to P. vivax. On the other hand, high RBC concentrations support a better and thick, well-developed PM and protect P. vivax from being killed. Further studies of this complex system may provide insights into other details of the malaria vector response to P. vivax infection

Coinfection with Zika Virus (ZIKV) and dengue virus results in preferential ZIKV transmission by vector bite to vertebrate host.

Background. Several tropical cities are permissive to Aedes aegypti and dengue virus (DENV) endemicity and have allowed for invasion and circulation of Zika virus (ZIKV) in the same areas. People living in arbovirus-endemic regions have been simultaneously infected with ?2 arboviruses. Methods. A. aegypti mosquitoes from Manaus, the capital city of Amazonas State in Brazil, were coinfected with circulating strains of DENV and ZIKV. The coinfected vectors were allowed to bite BALB/c mice. Results. A. aegypti from Manaus is highly permissive to monoinfection and coinfection with DENV and ZIKV and is capable of cotransmitting both pathogens by bite. Coinfection strongly influences vector competence, favoring transmission of ZIKV to the vertebrate host. Conclusions. This finding suggests that A. aegypti is an efficient vector of ZIKV and that ZIKV would be preferentially transmitted by coinfected A. aegypti. Coinfection in the vector population should be considered a new critical epidemiological factor and may represent a major public health challenge