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Zika virus (ZIKV) is an RNA flavivirus (Flaviviridae family) endemic in tropical and subtropical regions that is transmitted to humans by Aedes (Stegomyia) species mosquitoes. The two main urban vectors of ZIKV are Aedes aegypti and Aedes albopictus, which can be found throughout Brazil. This study investigated ZIKV infection in mosquito species sampled from urban forest fragments in Manaus (Brazilian Amazon). A total of 905 non-engorged female Ae. aegypti (22 specimens) and Ae. albopictus (883 specimens) were collected using BG-Sentinel traps, entomological hand nets, and Prokopack aspirators during the rainy and dry seasons between 2018 and 2021. All pools were macerated and used to inoculate C6/36 culture cells. Overall, 3/20 (15%) Ae. aegypti and 5/241 (2%) Ae. albopictus pools screened using RT-qPCR were positive for ZIKV. No supernatants from Ae. aegypti were positive for ZIKV (0%), and 15 out of 241 (6.2%) Ae. albopictus pools were positive. In this study, we provide the first-ever evidence of Ae. albopictus naturally infected with ZIKV in the Amazon region. [ABSTRACT FROM AUTHOR]

Globally, malaria and human immunodeficiency virus (HIV) are both independently associated with a massive burden of disease and death. While their co-infection has been well studied for Plasmodium falciparum, scarce data exist regarding the association of P. vivax and HIV. In this cohort study, we assessed the effect of HIV on the risk of vivax malaria infection and recurrence during a 4-year follow-up period in an endemic area of the Brazilian Amazon. For the purpose of this study, we obtained clinical information from January 2012 to December 2016 from two databases. HIV screening data were acquired from the clinical information system at the tropical hospital Fundação de Medicina Tropical Dr. Heitor Vieira Dourado (FMT-HVD). The National Malaria Surveillance database (SIVEP malaria) was utilized to identify malaria infections during a 4-year follow-up period after diagnosis of HIV. Both datasets were combined via data linkage. Between 2012 and 2016, a total of 42,121 people were screened for HIV, with 1569 testing positive (3.7%). Out of all the patients diagnosed with HIV, 198 had at least one episode of P. vivax malaria in the follow-up. In the HIV-negative group, 711 participants had at least one P. vivax malaria episode. When comparing both groups, HIV patients had a 6.48 [(5.37–7.83); P < 0.0001] (adjusted relative risk) greater chance of acquiring P. vivax malaria. Moreover, being of the male gender [ARR = 1.41 (1.17–1.71); P < 0.0001], Amerindian ethnicity [ARR = 2.77 (1.46–5.28); P < 0.0001], and a resident in a municipality of the Metropolitan region of Manaus [ARR = 1.48 (1.02–2.15); P = 0.038] were independent risk factors associated with an increased risk of clinical malaria. Education ≥ 8 years [ARR = 0.41 (0.26–0.64); P < 0.0001] and living in the urban area [ARR = 0.44 (0.24–0.80); P = 0.007] were associated to a lower risk of P. vivax malaria. A total of 28 (14.1%) and 180 (25.3%) recurrences (at least a second clinical malaria episode) were reported in the HIV-positive and HIV-negative groups, respectively. After adjusting for sex and education, HIV-positive status was associated with a tendency towards protection from P. vivax malaria recurrences [ARR = 0.55 (0.27–1.10); P = 0.090]. HIV status was not associated with hospitalizations due to P. vivax malaria. CD4 + counts and viral load were not associated with recurrences of P. vivax malaria. No significant differences were found in the distribution of parasitemia between HIV-negative and HIV-positive P. vivax malaria patients. Our results suggest that HIV-positive status is a risk factor for vivax malaria infection, which represents an additional challenge that should be addressed during elimination efforts. [ABSTRACT FROM AUTHOR]

Background: Brazil has considerably reduced the number of cases of malaria in recent years and aims to eradicate the disease completely, however, vivax malaria continues to be a major challenge for the health system. In this context, the key to building a successful elimination programme may lie in the knowledge and the perceptions of the health agents, the patients affected by the disease and the personnel responsible for malaria diagnosis, treatment and control at the local level. Methods: A qualitative study was undertaken in Manaus, capital of the state of Amazonas, Western Brazilian Amazon, using a sample of 33 patients who were being treated for malaria and 22 health agents who were working in malaria diagnosis, treatment and control at the local level. A semi-structured interview with a further thematic analysis was performed. Results: There are still many myths regarding malaria transmission and treatment that may hinder the sensitization of the population of this region in relation to the use of current control tools and elimination strategies, such as mass drug administration (MDA). Most health professionals reported that the abandonment of treatment for malaria by the patient is related to poor social conditions, the high incidence of alcoholism and the low level of schooling of the affected population. One negative perception, observed in both groups with regard to the use of insecticide-treated nets, is that they may cause skin irritations and allergies. Most patients and health professionals have described malaria as an impossible disease to eliminate because it is intrinsically associated with forest landscapes, and according to them, elimination would only be possible if there were a vaccine against malaria. Conclusion: In the Amazon, cultural perceptions about the etiology of this disease can influence the behaviour and practices that social groups adopt in relation to the different forms of living in a malaria-endemic context. Negative perceptions about malaria elimination can act as a barrier when trying to reach proper coverage for control strategies such as mosquito nets and MDA. [ABSTRACT FROM AUTHOR]