The house fly, Musca domestica L. (Diptera: Muscidae), is a global pest of humans and animals that carries scores of pathogens and costs up to $1 billion per year in the United States alone. Information is reviewed on recognition, distribution, biology, dispersal, and associations with microbes. Particular challenges of managing flies in different animal systems are discussed for swine, poultry, dairy cattle, beef feedlot, and equine operations. Effective fly management requires diligent monitoring and integration of cultural control, especially manure management, with mechanical control, traps, conservation or augmentative biological control, and judicious use of insecticides. House fly is notorious for developing insecticide resistance and its resistance status is summarized as of August 2020. Several critical research needs are identified. Monitoring systems and nuisance/action thresholds need improvement. Faster-killing strains and better formulations are needed to integrate pathogens into Integrated Pest management (IPM) programs. The use of parasitoids remains an inexact science with many questions remaining about species selection and release rates. New attractants are needed for use in traps and attract-and-infect/kill strategies. Screening of new active ingredients for toxicity should continue, including a rigorous assessment of essential oils and other botanicals. Rising global temperatures may affect the balance of the fly with natural enemies. An understanding of the fly microbiome may reveal unknown vulnerabilities, and much remains to be learned about how flies acquire, retain, and transmit human and animal pathogens. System-specific research is also needed to tailor fly IPM programs to individual animal systems, especially in organic and free-range animal production.

The transmission dynamics of mosquito-vectored pathogens are, in part, mediated by mosquito host-feeding patterns. These patterns are elucidated using blood meal analysis, a collection of serological and molecular techniques that determine the taxonomic identities of the host animals from which blood meals are derived. Modern blood meal analyses rely on polymerase chain reaction (PCR), DNA sequencing, and bioinformatic comparisons of blood meal DNA sequences to reference databases. Ideally, primers used in blood meal analysis PCRs amplify templates from a taxonomically diverse range of vertebrates, produce a short amplicon, and avoid co-amplification of non-target templates. Few primer sets that fit these requirements are available for the cytochrome c oxidase subunit I (COI) gene, the species identification marker with the highest taxonomic coverage in reference databases. Here, we present new primer sets designed to amplify fragments of the DNA barcoding region of the vertebrate COI gene, while avoiding co-amplification of mosquito templates, without multiplexed or nested PCR. Primers were validated using host vertebrate DNA templates from mosquito blood meals of known origin, representing all terrestrial vertebrate classes, and field-collected mosquito blood meals of unknown origin. We found that the primers were generally effective in amplifying vertebrate host, but not mosquito DNA templates. Applied to the sample of unknown mosquito blood meals, > 98% (60/61) of blood meals samples were reliably identified, demonstrating the feasibility of identifying mosquito hosts with the new primers. These primers are beneficial in that they can be used to amplify COI templates from a diverse range of vertebrate hosts using standard PCR, thereby streamlining the process of identifying the hosts of mosquitoes, and could be applied to next generation DNA sequencing and metabarcoding approaches. Female mosquitoes take blood meals from diverse vertebrate hosts, including amphibians, birds, mammals, reptiles, and fishes. Mosquito species vary in their host-use patterns. Identifying which mosquitoes feed from which hosts is critical to understanding how mosquitoes transmit disease-causing pathogens between vertebrates. Host-use patterns are determined by blood meal analysis. In modern blood meal analysis, host DNA is extracted from a mosquito, amplified in a polymerase chain reaction (PCR), sequenced, and identified. We designed new primers that selectively amplify a fragment of the DNA barcoding gene, cytochrome c oxidase subunit I (COI), of vertebrates, while avoiding that of mosquitoes. We validated the new primers in experiments using previously identified mosquito blood meals and mosquito DNA, and demonstrated their efficacy in identifying unknown mosquito blood meals. We found that the primers are well-suited to mosquito blood meal analysis applications. They are universal across vertebrates, target the COI DNA barcoding gene, and are effective in standard amplification reactions.

Aedes aegypti is an important vector for dengue virus and thus has been targeted with pyrethroid insecticides in many areas of the world. As such, resistance has been detected to several of these insecticides, including in China, but the mechanisms of the resistance are not well understood in this country. Using the World Health Organization larval mosquito bioassay, five field populations of Aedes aegypti from Southern China were characterized for their resistance to cypermethrin and cyhalothrin. RNA extraction with PCR amplification, cloning and sequencing of the sodium channel gene was followed by comparisons of susceptible and wild mosquito strains Additionally, genomic DNA was used for Allele-specific PCR (AS-PCR) genotyping of the sodium channel genes to detect S989P, V1016G and F1534C mutations and allow for correlation analysis of resistance expression for the different mutations. All wild strains expressed resistance to cypermethrin and cyhalothrin and the resistance expression between the two insecticides was highly correlated suggesting cross-resistance between these two pyrethroids. The AS-PCR technique effectively distinguished individual genotypes for all three mutations. Among the five wild strains tested, two strains carried all three mutations. Although the S989P and V1016G mutations were positively correlated to resistance expression of both pyrethroids, the F1534C mutation was negatively correlated. Our methodology proved highly reliable and will aid future detection of kdr mutations. The three sodium channel mutations were common in the Ae. aegypti strains sampled from Southern China. The V1016G mutation appears to be the most important kdr mutation in Ae. aegypti strains in Southern China.

Ongoing difficulties with successful urban mosquito management highlights the need to find novel management strategies to reduce the impact of mosquito vectors. To date, urban mosquito management can be summarized as dependent on the theme of recruiting the public to invest in their own protection. This effort takes the form of source reduction education programs and accompanying personal protection guidelines. However, the topical repellents that form the cornerstone of our personal protection guidelines are available in equal measure with spatial repellents. Spatial repellents commonly include volatile pyrethroids as active ingredients, which easily transition into a vapor phase, that are formulated into mosquito coils, vaporizers, emanators, or heated mats. These formulations are available on the global market. Consumers frequently choose spatial repellents, and existing literature indicates this choice has merits. This predicament forces integrated vector management to adapt to and understand tools that consumers selectively employ. At present, there is little information differentiating the effects of vapor-active pyrethroids from the contact efficacies we recognize from well-utilized pyrethroids. To address this, volatile pyrethroids need to have their multiple effects identified, defined, and described to maximize their utility for preventing mosquito biting and, thus, pathogen transmission. This article reviews the known utility of volatile pyrethroids in the context of repellency, acute symptoms, toxicity, and sublethal effects, and provides an overview of the evaluation methods used with volatile pyrethroids.

This paper examines the individual factors that influence prevalence rates of canine heartworm in the contiguous United States. A data set provided by the Companion Animal Parasite Council, which contains county-by-county results of over nine million heartworm tests conducted during 2011 and 2012, is analyzed for predictive structure. The goal is to identify the factors that are important in predicting high canine heartworm prevalence rates.