Margarita M. Correa

Background: Malaria constitutes an important public health problem in peri-urban neighbourhoods of Quibdó, Chocó Department, one of the most deprived areas of Colombia. This study evaluated sociodemographic and socio-economic characteristics and Plasmodium infection in two peri-urban neighbourhoods of Quibdó. Methods: A survey was provided to 136 individuals selected by non-probabilistic convenience sampling to evaluate sociodemographic, socio-economic and clinical aspects as well as Plasmodium infection and malaria prevention practices. Relationships between variables and Plasmodium infection were evaluated by an exploratory analysis. Results: Among participants, the malaria positivity rate was 8.8%. Northern participants mainly stayed/worked indoors, had better infrastructure and services, had access to bed nets and presented lower infection frequencies. Among the southern, more deprived population, outdoor work predominated; they experienced structural and protection resource gaps. Half of Plasmodium-infected participants had subclinical infection and nearly half carried gametocytes. Higher Plasmodium infection frequency was related with male sex, southern residence, lacking a bed net and deficient infrastructure. Conclusions: The results helped to identify the main sociodemographic and socio-economic characteristics relevant to transmission in peri-urban areas of Quibdó; they provide a preliminary perspective to strengthen control and prevention interventions through public health approaches and community participation.

Anopheles darlingi is the main malaria vector in the Neotropics. Despite their importance, little is known about the microbiota composition in areas where these vectors are found. Since the microbiota may influence host biology and vector competence, it is essential to understand these microbial communities in endemic regions. This study explores the bacterial and fungal communities in An. darlingi from three malaria-endemic areas in Colombia and examined how geography influences microbial composition. Mosquitoes were collected from the Bajo Cauca, Pacific and Amazonas regions, and their microbiota was characterized by amplifying and sequencing the 16 S rRNA V3-V4 region for bacteria and the ITS2 region for fungi. Analysis indicated greater alpha diversity in An. darlingi mosquitoes from the Amazonas region. Beta diversity findings demonstrated differences in bacterial and fungal community compositions across regions, especially between Amazonas and the other two regions. Additionally, the similarity of microbial communities declined slightly with increasing geographic distance. This study significantly advances our understanding of the microbiota associated with An. darlingi in endemic regions of Colombia, by revealing notable differences in bacterial and fungal community composition and abundance across diverse geographical populations. Importantly, these new insights extend beyond species and geographic boundaries by providing evidence of specific fungal communities linked to the vector, paving the way for innovative microbiota-based vector control strategies in malaria vector research. Graphical Abstract

Anopheles ( Anopheles ) pseudopunctipennis , involved in seasonal malaria transmission in the Andean foothills and American coastal areas, was previously proposed as a species complex based on cross‐mating experiments and population genetic analyses. In this work, a fragment of the mitochondrial gene cytochrome c oxidase subunit I or COI barcode region, and the nuclear second internal transcribed spacer (ITS2) were analysed in Colombian An. pseudopunctipennis s.l. specimens; the obtained sequences were compared to publicly available data using phylogeny and distance‐based species delimitation approaches. Assemble Species by Automatic Partitioning (ASAP) and coalescent‐based approaches provided strong evidence of at least two putative species on the American mainland, here designated as the North‐Central and Southern lineages. The North‐Central lineage is primarily found in southern/southwestern United States, Central America (Mexico and Honduras) and northwestern Colombia, while the Southern lineage is mainly detected in the Colombian Pacific and Argentina; there were some co‐occurrences of these lineages in the Colombian regions. The definition of these putative species is crucial for understanding their bionomy, ecology and potential role in malaria transmission. Further research, including a more comprehensive sampling and population genetic analysis, is needed to fully elucidate their evolutionary history and demographic dynamics.

Anopheles darlingi is a main malaria vector in the neotropical region, but its viral component is not well studied, especially in the neotropics. This work aimed to analyze the virome in Anopheles darlingi from malaria endemic regions of Colombia. Specimens were collected from the Bajo Cauca, Chocoan Pacific and northwestern Amazonas regions and analyzed using an RNA-Seq approach. Results revealed a variety of RNA viral sequences with homology to those of Insect-Specific Viruses belonging to Rhabdoviridae, Partitiviridae, Metaviridae, Tymoviridae, Phasmaviridae, Totiviridae, Ortervirales and Riboviria. Despite geographical and ecological differences among regions, the An. darlingi viral composition remains consistent in different areas, with a core group of viral operational taxonomic units-vOTUs shared by the populations. Furthermore, diversity analysis uncovered greater dissimilarities in viral sequence among mosquitoes from geographically distant regions, particularly evident between populations located at both sides of the Andes Mountain range. This study provides the first characterization of the metavirome in An. darlingi from Colombia and lays the foundation for future research on the complex interactions among viruses, hosts, and microbiota; it also opens a new line of investigation on the viruses in Anopheles populations of Colombia.

Several species of Anopheles mosquitoes (Arthropoda, Insecta, Diptera, Culicidae) are important in public health due to their role in malaria transmission. Of the more than 500 Anopheles species worldwide, 47 have been reported in Colombia, but only nine are known to transmit malaria. Taxonomic classification of these mosquitoes is complicated by the existence of species complexes and groups of closely related species that are difficult to distinguish based on morphological characteristics. However, molecular techniques have contributed to resolving taxonomic uncertainties, definition of molecular variants and facilitated the correction of erroneous taxonomic assignments. This study aimed to update the list of Anopheles species reported for Colombia. A species checklist was compiled by reviewing catalogs, publications, databases, and unpublished data. Only formally characterized species were included, along with their geographic range and ecological distribution. The final list includes 44 formally characterized Anopheles species belonging to five subgenera. The Nyssorhynchus subgenus constituted the largest group with 17 species and the widest distribution, occurring in 18 ecoregions. The Anopheles subgenus was the second largest group with 16 species and occurrences in 16 ecoregions. Sixty-six new presence records were added to the checklist. The updated Anopheles checklist, encompassing presence records and ecological distributions, enhances our understanding of Anopheles mosquito biodiversity. Furthermore, it contributes to improved public health by providing a foundation for targeted vector control interventions.

Malaria prevention and control programs are mainly oriented to vector control, timely diagnosis and adequate treatment. Malaria transmission is influenced by several factors, including biological and social aspects. Thus, it is relevant to consider community beliefs and practices to ensure sustainable prevention and control strategies. This study aimed to determine knowledge, attitudes and practices (KAP) towards malaria in an endemic locality in northwestern Colombia. Preliminary data were collected through a focus group discussion. Subsequently, a KAP survey was administered to the community. KAP scores were associated with both sociodemographic characteristics and with previous malaria infection. Focus group data revealed knowledge gaps and the absence of or having worn-out nets. Survey results showed that participants recognized a mosquito bite as the transmission mode (72.09%), followed by dirty water (44.19%), high fever (86.05%) and headache (79.07%) as the main symptoms. Regarding attitudes, 44.19% of the people would go to the hospital in the case of having symptoms. The most recognized practices for disease prevention were the use of mosquito nets (65.12%) and fans (23.26%). The results showed that some people had misconceptions about the disease transmission mode. The analysis showed significant associations of either female gender and homemaker occupation with a good knowledge [OR = 3.74, (p = 0.04), OR = 3.55, (p = 0.04), respectively] or female with a positive attitude towards malaria control and prevention [OR = 4.80, (p = 0.04)]. These results showed that the identified gaps in KAP require increasing education among the community in addition to applying public health prevention efforts. The data may be useful in designing malaria control strategies that involve community participation.

Anopheles species composition, abundance, and Plasmodium natural infection are important aspects to assess malaria transmission risk. In this study, these aspects were evaluated in a large number of localities in the most important malaria-endemic regions of Colombia. Mosquitoes were collected from 2012 to 2015 in 55 localities of northwestern and western Colombia. Anopheles species composition, abundance, and Plasmodium infection were estimated. A total of 13,218 Anopheles specimens were evaluated. The highest species richness was detected in the northwest, where the main vectors, An. albimanus (27.8%) and An. nuneztovari (26.7%), were the most abundant species. In the west, An. nuneztovari predominated (51.6%), followed by An. darlingi (29.2%). Six species were infected with Plasmodium, An. darlingi, An. nuneztovari, An. albimanus, An. calderoni, An. triannulatus, and An. braziliensis. Results showed that in these localities the main Colombian vectors are widely spread, which suggests a high malaria risk. Notably, this study is the first to report An. braziliensis from Colombia as being naturally infected with Plasmodium. Infection results for species that are suspected local vectors indicate the importance of conducting further studies to assess their epidemiological importance. This information provides the basis for the application of directed vector control strategies that are species-specific.

Anopheles mosquitoes are the vectors of Plasmodium, the etiological agent of malaria. In addition, Anopheles funestus and Anopheles gambiae are the main vectors of the O’nyong-nyong virus. However, research on the viruses carried by Anopheles is scarce; thus, the possible transmission of viruses by Anopheles is still unexplored. This systematic review was carried out to identify studies that report viruses in natural populations of Anopheles or virus infection and transmission in laboratory-reared mosquitoes. The databases reviewed were EBSCO-Host, Google Scholar, Science Direct, Scopus and PubMed. After the identification and screening of candidate articles, a total of 203 original studies were included that reported on a variety of viruses detected in Anopheles natural populations. In total, 161 viruses in 54 species from 41 countries worldwide were registered. In laboratory studies, 28 viruses in 15 Anopheles species were evaluated for mosquito viral transmission capacity or viral infection. The viruses reported in Anopheles encompassed 25 viral families and included arboviruses, probable arboviruses and Insect-Specific Viruses (ISVs). Insights after performing this review include the need for (1) a better understanding of Anopheles-viral interactions, (2) characterizing the Anopheles virome—considering the public health importance of the viruses potentially transmitted by Anopheles and the significance of finding viruses with biological control activity—and (3) performing virological surveillance in natural populations of Anopheles, especially in the current context of environmental modifications that may potentiate the expansion of the Anopheles species distribution.