Laboratory maintenance and care of Rhodnius prolixus (Hemiptera: Reduviidae) and other Triatominae.

Triatomines (Hemiptera: Reduviidae) are hematophagous insects that transmit Trypanosoma cruzi, the etiological agent for Chagas disease, to humans and other mammals. As medically important vectors, species such as Rhodnius prolixus (Hemiptera: Reduviidae) have long been used as a model organism for physiological studies. Laboratory rearing of triatomines is needed to support vector and parasite research.

Juvenile Hormone as a contributing factor in establishing midgut microbiota for fecundity and fitness enhancement in adult female Aedes aegypti.

Understanding the factors influencing mosquitoes' fecundity and longevity is important for designing better and more sustainable vector control strategies, as these parameters can impact their vectorial capacity. Here, we address how mating affects midgut growth in Aedes aegypti, what role Juvenile Hormone (JH) plays in this process, and how it impacts the mosquito's immune response and microbiota. Our findings reveal that mating and JH induce midgut growth.

Distribution and dynamics of Anopheles gambiae s.l. larval habitats in three Senegalese cities with high urban malaria incidence.

Urban malaria has become a challenge for most African countries due to urbanization, with increasing population sizes, overcrowding, and movement into cities from rural localities. The rapid expansion of cities with inappropriate water drainage systems, abundance of water storage habitats, coupled with recurrent flooding represents a concern for water-associated vector borne diseases, including malaria. This situation could threaten progress made towards malaria elimination in sub-Saharan countries, including Senegal, where urban malaria has presented as a threat to national elimination gains.

Urban malaria vector bionomics and human sleeping behavior in three cities in Senegal.

Background: Malaria is endemic in Senegal, with seasonal transmission, and the entire population is at risk. In recent years, high malaria incidence has been reported in urban and peri-urban areas of Senegal. An urban landscape analysis was conducted in three cities to identify the malaria transmission indicators and human behavior that may be driving the increasing malaria incidence occurring in urban environments.

Outbreak of Locally Acquired Mosquito-Transmitted (Autochthonous) Malaria - Florida and Texas, May-July 2023.

Eight cases of locally acquired, mosquito-transmitted (i.e., autochthonous) Plasmodium vivax malaria, which has not been reported in the United States since 2003, were reported to CDC from state health departments in Florida and Texas during May 18-July 17, 2023.

Adult Anesthesia, Feeding, and Sex Separation.

The adult stage is the only nonaquatic stage of the mosquito. Both male and female mosquitoes require access to a source of sugar to survive. In the insectary, a temperature of ∼27°C and 80% relative humidity and a cycle of 12 h light:12 h dark light, ideally with a sunrise and sunset period, are necessary minimum conditions to mimic their natural environment.

Larval Rearing.

Mosquito larvae are aquatic and go through four development stages (larval instars L1-L4) before pupation. Species vary in the duration of larval development, and a variety of external factors affect the development rate (e.g.

Considerations for Rearing and Maintaining in the Laboratory.

mosquitoes can transmit several human pathogens, including viruses such as o'nyong-nyong and parasites including spp. and spp., which cause malaria and filariasis, respectively.

Egg Collection, Disinfection, and Hatching.

Gravid (i.e., with fully developed eggs), mated females typically lay their eggs directly on water ∼48-72 h after a blood meal.

Pupa Collection and Sex Identification.

For most species, larval-pupal metamorphosis commences ∼1 wk after egg hatching. However, depending on the amount of food provided, HO temperature, and larval density, the pupation process can be accelerated or delayed. Synchronous pupation is difficult to accomplish consistently, and, thus, pupae need to be separated from larvae daily.

Countrywide insecticide resistance monitoring and first report of the presence of the L1014S knock down resistance in Niger, West Africa.

Background: Mass distribution of insecticide-treated nets (ITNs) is the principal malaria vector control strategy adopted by Niger. To better inform on the most appropriate ITN to distribute, the National Malaria Control Programme (NMCP) of Niger and its partners, conducted insecticide resistance monitoring in selected sites across the country.

Methods: The susceptibility of Anopheles gambiae sensu lato (s.

Evaluation of the residual efficacy and physical durability of five long-lasting insecticidal nets (LLINs) in Senegal.

Background: The preventive and curative strategies of malaria are based on promoting the use of long-lasting insecticidal nets (LLINs) and treating confirmed cases with artemisinin-based combination therapy. These strategies have led to a sharp decline in the burden of malaria, which remains a significant public health problem in sub-Saharan countries. The objective of this study was to determine and compare the residual efficacy of LLINs recommended by the World Health Organization.

Effective Oral RNA Interference (RNAi) Administration to Adult Anopheles gambiae Mosquitoes.

RNA interference has been a heavily utilized tool for reverse genetic analysis for two decades. In adult mosquitoes, double-stranded RNA (dsRNA) administration has been accomplished primarily via injection, which requires significant time and is not suitable for field applications. To overcome these limitations, here we present a more efficient method for robust activation of RNAi by oral delivery of dsRNA to adult Anopheles gambiae.

Evidence supporting deployment of next generation insecticide treated nets in Burkina Faso: bioassays with either chlorfenapyr or piperonyl butoxide increase mortality of pyrethroid-resistant Anopheles gambiae.

Background: Pyrethroid resistance poses a major threat to the efficacy of insecticide-treated nets (ITNs) in Burkina Faso and throughout sub-Saharan Africa, particularly where resistance is present at high intensity. For such areas, there are alternative ITNs available, including the synergist piperonyl butoxide (PBO)-based ITNs and dual active ingredient ITNs such as Interceptor G2 (treated with chlorfenapyr and alpha-cypermethrin). Before deploying alternative ITNs on a large scale it is crucial to characterize the resistance profiles of primary malaria vector species for evidence-based decision making.

Adaptation of ELISA detection of Plasmodium falciparum and Plasmodium vivax circumsporozoite proteins in mosquitoes to a multiplex bead-based immunoassay.

Background: Plasmodium spp. sporozoite rates in mosquitoes are used to better understand malaria transmission intensity, the relative importance of vector species and the impact of interventions. These rates are typically estimated using an enzyme-linked immunosorbent assay (ELISA) utilizing antibodies against the circumsporozoite protein of Plasmodium falciparum, Plasmodium vivax VK210 (P.

Delivery of Double-Stranded RNAs (dsRNAs) Produced by Escherichia coli HT115(DE3) for Nontransgenic RNAi-Based Insect Pest Management.

RNA interference (RNAi) is a powerful mechanism that can be exploited not only for physiology research but also for designing insect pest management approaches. Some insects cause harm by vectoring diseases dangerous to humans, livestock, or plants or by damaging crops. For at least a decade now, different insect control strategies that induce RNAi by delivering double stranded RNA (dsRNA) targeting essential genes have been proposed.

Surviving the Journey: Comparisons of Temperature-Stabilizing Materials for Living Arthropod Shipments.

Shipments of living mosquitoes and other arthropods require temperatures that are within a range that is compatible with their health and survival. In addition to express shipping and insulated containers, shipments often include materials that either store heat (i.e.

Widespread zoophagy and detection of Plasmodium spp. in Anopheles mosquitoes in southeastern Madagascar.

Background: Malaria is a top cause of mortality on the island nation of Madagascar, where many rural communities rely on subsistence agriculture and livestock production. Understanding feeding behaviours of Anopheles in this landscape is crucial for optimizing malaria control and prevention strategies. Previous studies in southeastern Madagascar have shown that Anopheles mosquitoes are more frequently captured within 50 m of livestock.

Cryoprotectant toxicity and hypothermic sensitivity among Anopheles larvae.

Laboratory rearing of mosquitoes is commonly practiced by researchers studying mosquito-borne infectious diseases and vector control methods. In the absence of cryopreservation methods to stabilize unique or genetically modified strains, mosquito lines must be continuously maintained, a laborious process that risks selection effects, contamination, and genetic drift. Towards the development of a cryopreservation protocol, several commonly used cryoprotectants were systematically characterized here both individually and as cocktails.

Delimiting cryptic morphological variation among human malaria vector species using convolutional neural networks.

Deep learning is a powerful approach for distinguishing classes of images, and there is a growing interest in applying these methods to delimit species, particularly in the identification of mosquito vectors. Visual identification of mosquito species is the foundation of mosquito-borne disease surveillance and management, but can be hindered by cryptic morphological variation in mosquito vector species complexes such as the malaria-transmitting Anopheles gambiae complex. We sought to apply Convolutional Neural Networks (CNNs) to images of mosquitoes as a proof-of-concept to determine the feasibility of automatic classification of mosquito sex, genus, species, and strains using whole-body, 2D images of mosquitoes.

Physiological responses to cryoprotectant treatment in an early larval stage of the malaria mosquito, Anopheles gambiae.

The development of cryopreservation protocols for Anopheles gambiae could significantly improve research and control efforts. Cryopreservation of any An. gambiae life stage has yet to be successful.

Trials of the Automated Particle Counter for laboratory rearing of mosquito larvae.

As a means of obtaining reproducible and accurate numbers of larvae for laboratory rearing, we tested a large-particle flow-cytometer type device called the 'Automated Particle Counter' (APC). The APC is a gravity-fed, self-contained unit that detects changes in light intensity caused by larvae passing the detector in a water stream and controls dispensing by stopping the flow when the desired number has been reached. We determined the accuracy (number dispensed compared to the target value) and precision (distribution of number dispensed) of dispensing at a variety of counting sensitivity thresholds and larva throughput rates (larvae per second) using < 1-day old Anopheles gambiae and Aedes aegypti larvae.

Attrition, physical integrity and insecticidal activity of long-lasting insecticidal nets in sub-Saharan Africa and modelling of their impact on vectorial capacity.

Background: Long-lasting insecticidal nets (LLINs) are the primary malaria prevention and control intervention in many parts of sub-Saharan Africa. While LLINs are expected to last at least 3 years under normal use conditions, they can lose effectiveness because they fall out of use, are discarded, repurposed, physically damaged, or lose insecticidal activity. The contributions of these different interrelated factors to durability of nets and their protection against malaria have been unclear.

Fluorescent markers rhodamine B and uranine for Anopheles gambiae adults and matings.

Background: Marking mosquitoes is vital for mark-release-recapture and many laboratory studies, but their small size precludes the use of methods that are available for larger animals such as unique identifier tags and radio devices. Fluorescent dust is the most commonly used method to distinguish released individuals from the wild population. Numerous colours and combinations can be used, however, dust sometimes affects longevity and behaviour so alternatives that do not have these effects would contribute substantially.