The extensive use of insecticides for vector control has led to the development of insecticide resistance in Aedes aegypti populations on a global scale, which has significantly compromised control actions. Insecticide resistance, and its underlying mechanisms, has been investigated in several countries, mostly in South American and Asian countries. In Africa, however, studies reporting insecticide resistance are rare and data on resistance mechanisms, notably knockdown resistance (kdr) mutations, is scarce. In this study, the recently described V410L kdr mutation is reported for the first time in old world Ae. aegypti populations, namely from Angola and Madeira island. Two additional kdr mutations, V1016I and F1534C, are also reported for the first time in populations from Angola and Cape Verde. Significant associations with the resistance phenotype were found for both V410L and V1016I individually as well as for tri-locus genotypes in the Angolan population. However, no association was found in Madeira island, probably due to the presence of a complex pattern of multiple insecticide resistance mechanisms in the local Ae. aegypti population. These results suggest that populations carrying the same kdr mutations may respond differently to the same insecticide, stressing the need for complementary studies when assessing the impact of kdr resistance mechanisms in the outcome of insecticide-based control strategies.
Z ika virus (ZIKV), first discovered in Uganda in 1947 and sporadically found in Africa and Asia, was long believed to only cause mild disease in humans (1). ZIKV isolates are classified into 1 of 2 lineages, representing the African and Asian genotypes. ZIKVs of the African lineage have been isolated from many regions of Africa (2), mostly through entomologic investigations, and serologic evidence suggests that ZIKV infections in humans are frequent (3). However, until the 2000s, the virus had seldom been detected in humans. The Asian lineage has spread throughout the Pacific, causing outbreaks in humans in Yap, Federated States of Micronesia, in 2007 and in French Polynesia during 2013-2014, where an association with neurologic afflictions was first detected (4). Zika cases were first reported in Brazil in May 2015, and from there, the virus quickly spread to most of the Americas (5). The high number of cases led to the discovery of an association between congenital ZIKV infection and neonatal neurologic complications, particularly microcephaly (6,7). In October 2015, an epidemic of rash, conjunctivitis, and arthralgia was noted by physicians in Praia, the capital of Cape Verde, an archipelago nation located in the Atlantic Ocean, west of the coast of Senegal. Blood samples sent to the regional reference laboratory of the Institut Pasteur de Dakar (Dakar, Senegal) confirmed the epidemic involved ZIKV infection. By the end of the outbreak in May 2016, a total of 7,580 suspected Zika cases and 18 microcephaly cases were
The explosive emergence of Zika virus (ZIKV) across the Pacific and Americas since 2007 was associated with hundreds of thousands of human cases and severe outcomes, including congenital microcephaly caused by ZIKV infection during pregnancy. Although ZIKV was first isolated in Uganda, Africa has so far been exempt from large-scale ZIKV epidemics, despite widespread susceptibility among African human populations. A possible explanation for this pattern is natural variation among populations of the primary vector of ZIKV, the mosquito Aedes aegypti. Globally invasive populations of Ae. aegypti outside of Africa are considered effective ZIKV vectors because they are human specialists with high intrinsic ZIKV susceptibility, whereas African populations of Ae. aegypti across the species’ native range are predominantly generalists with low intrinsic ZIKV susceptibility, making them less likely to spread viruses in the human population. We test this idea by studying a notable exception to the patterns observed across most of Africa: Cape Verde experienced a large ZIKV outbreak in 2015 to 2016. We find that local Ae. aegypti in Cape Verde have substantial human-specialist ancestry, show a robust behavioral preference for human hosts, and exhibit increased susceptibility to ZIKV infection, consistent with a key role for variation among mosquito populations in ZIKV epidemiology. These findings suggest that similar human-specialist populations of Ae. aegypti in the nearby Sahel region of West Africa, which may be expanding in response to rapid urbanization, could serve as effective vectors for ZIKV in the future.
Context The first case of COVID-19 in Cabo Verde was confirmed on March 19, 2020. Since the beginning of the pandemic in the country, the government and health authorities have adopted restrictive measures to prevent the spread of SARS-CoV- 2 and well as defined risk communication and community involvement strategies. The present study aimed at assessing the knowledge, attitudes, and practices of the Cape Verdean resident population towards COVID-19, to support the government and the national health system in the definition of public health policies related to COVID-19. Method A cross-sectional study was conducted among 1996 participants aged 16 years old and above. Data collected from April 5 to April 12, 2020, via an online self-reporting questionnaire adapted from a Chinese study. Descriptive statistics, chi-square tests, simple and multiple linear regression analyses were performed to determine factors associated with knowledge, attitudes, and practices towards COVID-19. Results The overall correct answer rate related to the knowledge about COVID-19 was 82% (9/11 * 100), 1970 (98.70%) of the participants declared they had stayed at home in recent days, 1926 (96.49%) had not attended parties, funerals or crowded places and 1860 (93.19%) confirmed changes in daily routines due to COVID-19. The majority of the participants, 1797 (90.26%), preferred receiving information about COVID-19 in Portuguese and trusted information transmitted by health professionals. Furthermore, television, radio, and newspapers were the preferred means of transmitting information about COVID-19. Participants' knowledge influenced COVID-19 prevention and control practices (rho = 0.119; p = 0.000). Conclusions These findings showed that the resident population had a good level of knowledge about COVID-19; however, there is a need to use more effective strategies to improve attitudes and practices towards COVID-19 to attain better results in controlling the pandemic in Cabo Verde.
Background: Mosquito-borne viruses, such as Zika, dengue, yellow fever, and chikungunya, are important causes of human diseases nearly worldwide. The greatest health risk for arboviral disease outbreaks is the presence of the most competent and highly invasive domestic mosquito, Aedes aegypti. In Cabo Verde, two recent arbovirus outbreaks were reported, a dengue outbreak in 2009, followed by a Zika outbreak in 2015. This study is the first entomological survey for Ae. aegypti that includes all islands of Cabo Verde archipelago, in which we aim to evaluate the actual risk of vector-borne arboviruses as a continuous update of the geographical distribution of this species. Methods: In order to assess its current distribution and abundance, we undertook a mosquito larval survey in the nine inhabited islands of Cabo Verde from November 2018 to May 2019. Entomological larval survey indices were calculated, and the abundance analyzed. We collected and identified 4045 Ae. aegypti mosquitoes from 264 positive breeding sites in 22 municipalities and confirmed the presence of Ae. aegypti in every inhabited island. Results: Water drums were found to be the most prevalent containers (n = 3843; 62.9%), but puddles (n = 27; 0.4%) were the most productive habitats found. The overall average of the House, Container, and Breteau larval indices were 8.4%, 4.4%, and 10.9, respectively. However, 15 out of the 22 municipalities showed that the Breteau Index was above the epidemic risk threshold. Conclusion: These results suggest that if no vector control measures are considered to be in place, the risk of new arboviral outbreaks in Cabo Verde is high. The vector control strategy adopted must include measures of public health directed to domestic water storage and management.
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