Vector Biology Research Articles

Marine Algal Toxins and Public Health: Insights from Shellfish and Fish, the Main Biological Vectors

Exposure to toxigenic harmful algal blooms (HABs) can result in widely recognized acute poisoning in humans. The five most commonly recognized HAB-related illnesses are diarrhetic shellfish poisoning (DSP), paralytic shellfish poisoning (PSP), amnesic shellfish poisoning (ASP), neurotoxic shellfish poisoning (NSP), and ciguatera poisoning (CP). Despite being caused by exposure to various toxins or toxin analogs, these clinical syndromes share numerous similarities. Humans are exposed to these toxins mainly through the consumption of fish and shellfish, which serve as the main biological vectors. However, the risk of human diseases linked to toxigenic HABs is on the rise, corresponding to a dramatic increase in the occurrence, frequency, and intensity of toxigenic HABs in coastal regions worldwide. Although a growing body of studies have focused on the toxicological assessment of HAB-related species and their toxins on aquatic organisms, the organization of this information is lacking. Consequently, a comprehensive review of the adverse effects of HAB-associated species and their toxins on those organisms could deepen our understanding of the mechanisms behind their toxic effects, which is crucial to minimizing the risks of toxigenic HABs to human and public health. To this end, this paper summarizes the effects of the five most common HAB toxins on fish, shellfish, and humans and discusses the possible mechanisms.

Representative honey bee viruses do not replicate in the small hive beetle, Aethina tumida Murray

The small hive beetle (SHB), Aethina tumida Murray, is an invasive pest of the honey bee and causes significant damage through the consumption of colony resources and brood. Two assumptions related to honey bee virus transmission have been made about SHB: first, that SHB vectors honey bee viruses and second, that these viruses replicate in SHB based on the detection of both positive and negative strand viral genomic RNA within SHB. To clarify the role of SHB in virus transmission, we sought to address whether selected honey bee viruses replicate in SHB. Sequences derived from five honey bee viruses were identified in the transcriptomes of field-caught SHB from the U.S., but not in those of lab-reared SHB, suggesting that these viruses do not replicate in SHB. To elucidate whether the representative viruses, Israeli acute paralysis virus (IAPV; Dicistroviridae) and Deformed wing virus (DWV; Iflaviridae) replicate in SHB, we tested for replication in vitro in an SHB-derived cell line (BCIRL-AtumEN-1129-D6). Following treatment of the cell line with viral particles or viral RNA, the number of virus genomes was monitored by reverse transcription quantitative PCR (RT-qPCR). In contrast to the positive control, IAPV and DWV RNA levels steadily decreased over a period of 8 days. Collectively, these results from bioinformatic observations and in vitro experiments indicate that IAPV and DWV do not replicate in SHB. These results are consistent with the host specificity of most insect viruses within a single insect order and indicate that while SHB may serve as a mechanical vector of honey bee viruses within and between hives, this insect does not serve as a biological vector for these honey bee viruses.

Empowering Communities through Citizen Science: Dengue Prevention in Córdoba.

Traditional mosquito vector control methods have proved ineffective in controlling the spread of dengue fever. This study aimed to assess the effectiveness of community engagement through student-led science in promoting dengue prevention and socioecological factors in the temperate urban city of Córdoba, Argentina. It assesses community perceptions, knowledge, attitudes, and preventive practices regarding dengue fever and its vector. Results showed a significant increase in knowledge about the vector and the disease and respondents' adoption of good preventive practices. Student-led science was identified as a valuable tool for reaching households and leading to behavior changes at home. Furthermore, the findings highlighted the need for school programs to address vector biology and vector-borne disease prevention all year round. This study provides invaluable insights into the effectiveness of community engagement through student-led science to promote dengue prevention and socioecological factors. The findings suggest that this approach could be used to control the spread in other regions affected by the disease.

Dear Malaria: Deer Have Malaria! Prevalence ofPlasmodium odocoilei Infection in White-tailed deer in Pennsylvania

Abstract Background To combat antimalarial treatment resistance, better understanding of malaria pathogenesis is needed, but existing animal model have various limitations. Notably, prevailing murine models require laboratory infection of non-natural host species. In 2016, the parasite Plasmodium odocoilei was identified in white-tailed deer (Odocoileus virginianus). This was the first non-human mammalian malaria parasite identified in North America, representing a novel naturally occurring model system that allows for integrated examination of host, vector, and systems parasite biology. In addition, sickle hemoglobinopathy is exceptionally common among white-tailed deer, occurring in up to 60% of apparently healthy animals. In humans, the prevalence of sickle hemoglobinopathy in individuals with ancestry from malaria-endemic regions is due to the protective effects of sickle trait against severe malaria. Thus, the white-tailed deer-P. odocoilei system represents the only known naturally occurring model of the association between malaria parasite biology and sickle cell disease. Pennsylvania white-tailed deer have not previously been surveyed for infection. In this study, we determined P. odocoilei prevalence in a sample of 170 Pennsylvania white-tailed deer. Methods We amplified the CytB gene of P. odocoilei by nested PCR from DNA extracted from homogenized white-tailed deer tongue tissue obtained from the PennVet Wildlife Futures Program. We confirmed samples screening positive on gel electrophoresis via unprimed sequencing (Plasmidsaurus, USA) and NCBI-BLAST analysis. Results We estimate the prevalence of P. odocoilei infection in Pennsylvania white-tailed deer to be 0.6% (1 of 170 samples). Sequencing of the positive sample revealed a 621-bp sequence with close sequence identity to previous North American isolates of P. odocoilei (query cover 91-100%, percent identity 99.34-100.00%). Biobank metadata showed the positive sample originated from a roadkilled yearling male picked up at GPS coordinates (40.8423, -79.0409) on August 15, 2022. Conclusion P. odocoilei is endemic to Pennsylvania white-tailed deer. Our future directions include screening of additional samples, determination of host hemoglobin allele frequencies, detailed parasite genetic studies, and entomologic studies to elucidate vector biology. In addition, granular sample metadata collected by the PennVet Wildlife Futures Program will allow us to analyze the effects of geographic, demographic, and temporal variables on epidemiology. In sum, our survey data empowers future Pennsylvania-based studies to take advantage of the only known naturally occurring animal model of sickling and its association with protozoan infection.

Bridging the gaps: prioritizing research strategies for enhanced malaria control and elimination.

Malaria continues to be a significant global health challenge, with millions of cases and hundreds of thousands of deaths reported annually. To combat this disease effectively, it is imperative to identify and address significant research gaps in malaria control and elimination efforts. This review synthesizes current knowledge and highlights critical gaps in several crucial areas of malaria research. Firstly, we discuss the complexities of vector biology and control, emphasizing the need for a deeper understanding of vector behavior, particularly in urban settings. Secondly, the study examines the challenges posed by drug resistance and the urgent need for alternative treatment strategies and novel drug targets. Thirdly, the review explores the ongoing quest for an effective malaria vaccine, underscoring the importance of understanding immunological correlates of protection. The study also explores medication resistance genes and genomic epidemiology, highlighting the need for more investigation into potential targets for drugs and vaccine candidates. Furthermore, it addresses the socioeconomic and environmental determinants of malaria transmission, highlighting the importance of integrating multidisciplinary approaches to address transmission dynamics. The study concludes with a discussion of how malaria transmission is impacted by climate change and the necessity of research to guide adaptation measures.

Article Review: The Role of Blood-sucking Insect Vectors in the Spread of Jembrana Disease in Bali Cattle

ABSTRACT. Jembrana disease is a contagious disease in cattle and causes enormous economic losses for farmers. This disease, known as bovine lentivirus, was first reported in 1964 in Jembrana District. Jembrana disease specifically attacks Bali cattle at various ages. The cause of this disease is a lentivirus from the Retoviridae family. Jembrana disease transmission occurs by direct contact and is mediated by blood-sucking insect vectors. Not all blood-sucking insects can be vectors for Jembrana disease. Some blood-sucking insects capable of spreading Jembrana disease are Tabanus rubidus flies Culicoides sp mosquitoes, and Aedes lineatopennis, which act as mechanical vectors. As for the Boophilus microplus tick, it is suspected that it acts as a biological vector. Even after re-testing the tick, it could not prove its role as a biological vector for JDV. Prevention and control of this disease can be carried out by vaccination, biosecurity, biosafety, administration of vitamins, isolation of infected livestock, and control of blood-sucking insect vectors by administering insecticides to cages.

Molecular evidence of pathogens and endosymbionts in the black horse fly Osca lata (Diptera: Tabanidae) in Southern Chile.

Little is known about the role of horse flies in potential pathogen transmission in Chile. This study provides evidence of the molecular detection of microorganisms in southern Chile. In the present study, adult Osca lata horse flies were trapped from Punucapa (39°45'06"S/73°16'08"W, Región de Los Ríos) and Puyehue (40°39'10"S/72°10'57"W, Región de Los Lagos), Chile. Among the 95 samples analyzed by PCR using specific primers, microorganisms were detected in 23.2% (n = 22) of the samples. Rickettsia spp. DNA was detected in 15.8% (n = 15) of the samples, Trypanosomatidae DNA in 5.3% (n = 5) of the samples, and filarial DNA in 2.1% (n = 2) of the samples. This study found that horse flies in the region are capable of carrying a variety of both parasites and endosymbionts. Further research is needed to understand the specific impact of horse flies as mechanical or biological vectors and develop effective control measures to prevent the spread of any microorganisms associated with disease.

Faeces of Capybara (Hydrochoerus hydrochaeris) as a Bioindicator of Contamination in Urban Environments in Central-West Brazil

Along with exposure to parasites and other biological disease vectors, animal faeces can also contain heavy metals and metalloids. We quantified metals, metalloids, and non-metals in the faeces of capybara (Hydrochoerus hydrochaeris) that live in parks in the city of Campo Grande (Brazil). Quantification of metalloids was obtained after acid digestion using an inductively coupled plasma optical emission spectrometer. Higher mean concentrations in mg/kg of aluminium (Al) (140.322), arsenic (As) (0.010), cadmium (Cd) (1.042), chromium (Cr) (26.866), cobalt (Co) (1.946), copper (Cu) (50.764), lead (Pb) (8.762), manganese (Mn) (291.469), molybdenum (Mo) (3.634), nickel (Ni) (5.475), and zinc (Zn) (100.027) were quantified in samples of faeces of capybara that live on the banks of a lagoon that receives input from streams that cross the city. According to the risk assessment, potential risks to the health of children and adults may occur due to the presence of Al, As, Cd, Co, Cu, and Mn through involuntary oral ingestion of faeces, via inhalation and dermal contact. The hazard index (HI) due to oral ingestion was greater than 1 for children and adults. Therefore, we believe that faeces of H. hydrochaeris can be considered as a bioindicator of environmental pollution in urban parks.

Rodent Ecology and Etiological Investigation in China: Results from Vector Biology Surveillance - Shandong Province, China, 2012-2022.

Rodents are hosts of a wide range of zoonotic disease pathogens which threaten human health. However, comprehensive investigations of rodent ecology and etiology in Shandong are lacking. Thus, we aimed to analyze rodent ecology and infection with relevant pathogens in Shandong Province, China. Rodent survey data collected from 2012 to 2022 in Shandong Province were used in this study. Rodents captured from 2020 to 2022 were identified to species and tested for pathogens. From 2012 to 2022, 4,145 rodents were captured, with an average capture rate of 0.70%. High capture rates were observed in rural residential areas and other habitats, such as farmland and forestland. Rattus norvegicus (R. norvegicus) was the dominant species, followed by Mus musculus (M. musculus). The regions with the highest capture rates of R. norvegicus were Dongying (0.82%) and Heze (0.63%), while M. musculus was more prevalent in Dongying (0.81%) and Weihai (0.56%). Rodent capture rates were highest between March and September. The positive detection rates of Hantavirus (HV), Leptospira interrogans (L. interrogans), Rickettsia typhi (R. typhi), Anaplasma phagocytophilum (A. phagocytophilum), and Francisella tularensis (F. tularensis) in rodents were 2.58%, 1.10%, 0.94%, 0.16%, and 0.19%, respectively. The rodent capture rate in human habitation environments has trended downward in Shandong Province, with R. norvegicus and M. musculus being the dominant species. Rodent infection risk from HV, L. interrogans, and R. typhi showed seasonal variation. Strengthening rodent surveillance and maintaining a low capture rate of host animals could be pivotal for preventing and controlling relevant rodent-borne diseases in high-risk areas.

A regional One Health approach to the risk of invasion by Anopheles stephensi in Mauritius.

Anopheles stephensi is an invasive malaria vector in Africa that threatens to put an additional 126 million people at risk of malaria if it continues to spread. The island nation of Mauritius is highly connected to Asia and Africa and is at risk of introduction due to this connectivity. For early detection of An. stephensi, the Vector Biology and Control Division under the Ministry of Health in Mauritius, leveraged a well-established Aedes program, as An. stephensi is known to share Aedes habitats. These efforts triggered multisectoral coordination and cascading benefits of integrated vector and One Health approaches. Beginning June 2021, entomological surveys were conducted at points of entry (seaport, airport) and on ships transporting livestock in collaboration with the Civil Aviation Department, the Mauritian Port Authority and National Veterinary Services. A total of 18, 39, 723 mosquito larval surveys were respectively conducted in the airport, seaport, and other localities in Mauritius while two, 20, and 26 adult mosquito surveys were respectively conducted in the airport, seaport, and twenty-six animal assembly points. Alongside adult mosquito surveys, surveillance of vectors of veterinary importance (e.g.- Culicoides spp.) was also carried out in collaboration with National Parks and Conservation Service and land owners. A total of 8,428 adult mosquitoes were collected and 1,844 larval habitats were positive for mosquitoes. All collected mosquitoes were morphologically identified and 151 Anopheles and 339 Aedes mosquitoes were also molecularly characterized. Mosquito species detected were Aedes albopictus, Anopheles arabiensis, An. coustani, An. merus, Culex quinquefasciatus, Cx. thalassius and Lutzia tigripes. Anopheles stephensi was not detected. The One Health approach was shared with the French Agricultural Research Centre for International Development (CIRAD), strengthening collaboration between Mauritius and Réunion Island on vector surveillance at entry points and insecticide resistance monitoring. The Indian Ocean Commission (IOC) was also alerted to the risk of An. stephensi, leading to regional efforts supporting trainings and development of a response strategy to An. stephensi bringing together stakeholders from Comoros, Madagascar, Mauritius, Réunion Island and Seychelles. Mauritius is a model system showing how existing public health entomology capabilities can be used to enhance vector surveillance and control and create multisectoral networks to respond to any emerging public and veterinary health vector-borne disease threat.

Symbiotic bacteria Sodalis glossinidius, Spiroplasma sp and Wolbachia do not favour Trypanosoma grayi coexistence in wild population of tsetse flies collected in Bobo-Dioulasso, Burkina Faso.

Tsetse flies, the biological vectors of African trypanosomes, have established symbiotic associations with different bacteria. Their vector competence is suggested to be affected by bacterial endosymbionts. The current study provided the prevalence of three tsetse symbiotic bacteria and trypanosomes in Glossina species from Burkina Faso. A total of 430 tsetse flies were captured using biconical traps in four different collection sites around Bobo-Dioulasso (Bama, Bana, Nasso, and Peni), and their guts were removed. Two hundred tsetse were randomly selected and their guts were screened byPCR for the presence of Sodalis glossinidius, Spiroplasmasp., Wolbachia and trypanosomes. Of the 200 tsetse, 196 (98.0%) were Glossina palpalis gambienseand 4 (2.0%) Glossina tachinoides. The overall symbiont prevalence was 49.0%, 96.5%, and 45.0%, respectively for S. glossinidius, Spiroplasma and Wolbachia. Prevalence varied between sampling locations: S. glossinidius(54.7%, 38.5%, 31.6%, 70.8%); Spiroplasma (100%, 100%, 87.7%, 100%); and Wolbachia(43.4%, 38.5%, 38.6%, 70.8%),respectively in Bama, Bana, Nasso and Peni. Noteworthy, no G. tachhnoideswas infected by S. glossinidius and Wolbachia, but they were all infected by Spiroplasma sp. A total of 196 (98.0 %) harbored at least one endosymbionts. Fifty-five (27.5%) carried single endosymbiont. Trypanosomes were found only in G.p. gambiense, but not G. tachinoides. Trypanosomes were present in flies from all study locations with an overall prevalence of 29.5%. In Bama, Bana, Nasso, and Peni, the trypanosome infection rate was respectively 39.6%, 23.1%, 8.8%, and 37.5%. Remarkably, only Trypanosoma grayi was present. Of all trypanosome-infected flies, 55.9%, 98.3%, and 33.9% hosted S. glossinidius, Spiroplasma sp and Wolbachia, respectively. There was no association between Sodalis, Spiroplasma and trypanosome presence, but there was a negative association with Wolbachia presence. We reported1.9 times likelihood of trypanosome absence when Wolbachia was present. This is the first survey reporting the presence of Trypanosoma grayi in tsetse from Burkina Faso. Tsetse from these localities were highly positive for symbiotic bacteria, more predominantly with Spiroplasma sp. Modifications of symbiotic interactions may pave way for disease control.

Microbial Metagenomics Revealed the Diversity and Distribution Characteristics of Groundwater Microorganisms in the Middle and Lower Reaches of the Yangtze River Basin.

Groundwater is one of the important freshwater resources on Earth and is closely related to human activities. As a good biological vector, a more diverse repertory of antibiotic resistance genes in the water environment would have a profound impact on human medical health. Therefore, this study conducted a metagenomic sequencing analysis of water samples from groundwater monitoring points in the middle and lower reaches of the Yangtze River to characterize microbial community composition and antibiotic resistance in the groundwater environment. Our results show that different microbial communities and community composition were the driving factors in the groundwater environment, and a diversity of antibiotic resistance genes in the groundwater environment was detected. The main source of antibiotic resistance gene host was determined by correlation tests and analyses. In this study, metagenomics was used for the first time to comprehensively analyze microbial communities in groundwater systems in the middle and lower reaches of the Yangtze River basin. The data obtained from this study serve as an invaluable resource and represent the basic metagenomic characteristics of groundwater microbial communities in the middle and lower reaches of the Yangtze River basin. These findings will be useful tools and provide a basis for future research on water microbial community and quality, greatly expanding the depth and breadth of our understanding of groundwater.

Resolution of cryptic mosquito species through wing morphometrics

Mosquitoes are medically important insects, and accurate species identification is crucial to understanding vector biology, forming the cornerstone of successful vector control programs. Identification is difficult owing to morphologically similar species. Wing morphometrics can provide a simple, fast, and accurate way to classify species, and using it as a method to differentiate vector species among its cryptic congeners has been underexplored. Using a total of 227 mosquitoes and 20 landmarks per specimen, we demonstrated the utility of wing morphometrics in differentiating species two groups occurring in sympatry – Culex (Culex) vishnui group and Culex (Lophoceraomyia) subgenus, as well as explored population-level variation in the wing shape of Aedes albopictus across habitats. Cytochrome oxidase subunit I (COI) gene region was sequenced to validate the morphological and morphometric identification. Procrustes ANOVA regression and CVA based on wing shape reflected that the wing landmarks across all species differed significantly, and leave-one-out cross validation revealed an overall high accuracy of >97% for the two Culex groups. Wing morphometrics uncovered population-level variation within Aedes albopictus, but cross validation accuracy was low. Overall, we show that wing geomorphometric analysis is able to resolve cryptic Culex species (including vectors) occurring sympatrically, and is a robust tool for identifying mosquitoes reliably.

Culex quinquefasciatus Mosquitoes Resist Acquisition of Methicillin-Resistant Staphylococcus aureus: Insights from Field and Laboratory Studies.

The emergence of antimicrobial resistance (AMR) in pathogens and their spillover into the environment have become a global public health menace. Insects can acquire these pathogens from the environment and would serve as mechanical and biological vectors. The current study assessed the ability of Culex quinquefasciatus mosquitoes to acquire methicillin-resistant Staphylococcus aureus (MRSA) through the exposure of the mosquitoes to the pathogen via rearing water, blood feed, or a feeding membrane under laboratory conditions. In addition, mosquito immatures collected from their habitat in the vicinity of hospitals, veterinary dispensaries, and butcher shops at 15 study sites in Puducherry were screened for MRSA infection. All samples were subjected to the culture-based isolation of S. aureus from the surface and homogenate. The presence of the S. aureus-specific nuc gene and the genes that confer resistance to methicillin (mecA and mecC) were screened using PCR tests. MRSA was not evident either on the external surface or in the homogenate of the mosquitoes emerging from the larvae reared in the MRSA-spiked water or those fed with MRSA through blood or smeared membranes. Furthermore, the presence of MRSA was not evident in any of the field-caught mosquitoes. Hence, we conclude that C. quinquefasciatus mosquitoes are impervious to MRSA colonization.

Skilful probabilistic medium‐range precipitation and temperature forecasts over Vietnam for the development of a future dengue early warning system

AbstractDengue fever is a source of substantial health burden in Vietnam. Given the well‐established influence of temperature and precipitation on vector biology and disease transmission, predictions of meteorological variables, such as those issued by ECMWF as a world‐leading provider of global ensemble forecasts, are likely to be valuable model inputs to a future dengue early warning system. In the absence of established verification at municipal and regional scales, this study assesses the skill of rainy season (May–October) ensemble precipitation and 2‐m temperature retrospective forecasts over North and South Vietnam initialized for dates during the period 2001–2020, evaluated against the ERA5 reanalysis for the same period. Forecasts are found to be significantly skilful compared with both climatology and persistence for lead times up to 10 days, including for cumulative precipitation values considered against independent rain gauge data. Rank histograms demonstrate that ensembles generally avoid excessive bias and consistently positive CRPSS values indicate substantial skill for temperature and cumulative precipitation forecasts for all spatial scales considered, despite differences in rainy season characteristics between North and South Vietnam. This forecast reliability demonstrates that meteorological input data based on ECMWF ensemble forecasts would add appreciably more value to the development of a future dengue early warning system compared to reference forecasts like climatology or persistence. These results raise hope for further exploration of predictive skill for relevant meteorological variables, particularly focused on their downscaling to produce district‐level epidemiological forecasts for urban areas where dengue is most prevalent.

Diversity of symbiotic bacteria in the reproductive tracts and midgut of Culex pipiens

Background: Culex pipiens is considered a vector for the transmission of infectious, viral, and parasitic diseases. To control this mosquito vector, investigating symbiotic bacteria colonized inside the mosquitoes’ organs to impede the transmission of pathogens has been of recent interest to researchers. Methods: This revision was intended to provide a comprehensive overview of the diversity of endosymbiont bacteria residing in different tissues of Cx. pipiens globally by using reports in Google Scholar, PubMed, and Science Direct until May 2024. Result: The results showed that more than 50 bacterial genera have been reported in Culex tissues, in which the bacterial diversity was higher in the midgut than eggs or the whole body in Cx. pipiens. More than 65% of samples were insect-reared mosquitoes than wild types. Various methods based on culture-dependent and culture-independent approaches followed by molecular techniques such as 16SrRNA Illumina sequencing, Next Generation Sequencing (NGS), RNA shotgun metagenomic sequencing (RNA-seq), RTPCR, and MALDI-TOF MS have been used for the recognition of bacteria at genera or species levels. The most favorable gene for molecular analysis via PCR is 16SrRNA; however, the wsp gene was another candidate used for identification of the bacterial community. Conclusion: These results provide a library of defined bacteria associated with Cx. pipiens. The characterization of tissue-specific and host-specific bacterial communities sheds light on further studies pursuing the functional role of endosymbiont organisms in control strategies and vector biology.

Hemotrophic Mycoplasmas-Vector Transmission in Livestock.

Hemotrophic mycoplasmas (HMs) are highly host-adapted and specialized pathogens infecting a wide range of mammals including farm animals, i.e., pigs, cattle, sheep, and goats. Although HMs have been known for over 90 years, we still do not know much about the natural transmission routes within herds. Recently, it has been repeatedly discussed in publications that arthropod vectors may play a role in the transmission of HMs from animal to animal. This is mainly since several HM species could be detected in different potential arthropod vectors by PCR. This review summarizes the available literature about the transmission of bovine, porcine, ovine, and caprine HM species by different hematophagous arthropod vectors. Since most studies are only based on the detection of HMs in potential vectors, there are rare data about the actual vector competence of arthropods. Furthermore, there is a need for additional studies to investigate, whether there are biological vectors in which HMs can multiply and be delivered to new hosts.

Distribution trends of bovine Anaplasma marginale in Iowa, based upon veterinary diagnostic lab submissions from 2017-2022

Anaplasma marginale is the common etiological agent of bovine anaplasmosis. Infection results in erythrocyte de­struction leading to the clinical signs of anemia, hypoxia, abortion, jaundice and sudden death. Cattle that survive this acute phase or have lower levels of initial bacteremia become chronic, persistent carriers. Carrier animals serve as reser­voirs for the organism and allow infection to spread via me­chanical or biological vectors, to susceptible herdmates. The objective of this study was to report the distribution trends of A. marginale positive test results during a 5-year period in Iowa. This study evaluated Iowa State University Veterinary Diagnostic Lab (ISU VDL) testing results from bovine cases submitted from January 1, 2017 to January 1, 2022, for molecu­lar and serological detection of all stages of anaplasmosis. Cattle residing in Iowa with positive results for PCR or com­petitive ELISA were included in the analysis. The state was divided into 4 geographical districts (1 = northeast, 2 = south­east, 3 = southwest, and 4 = northwest) and the number of pos­itive tests in each district was determined. Total positive tests by district included: northeast 282; southeast 277; southwest 223; northwest 281. Disease spatial analysis mapping, based upon geographic longitude and latitude location of herds with positive diagnostic tests, illustrate progressive disease expan­sion from the southern counties of Iowa, near the Missouri border, into the northern parts of Iowa. These results suggest that A. marginale has developed a widespread distribution across the state of Iowa.

Research and Prevention and Control Countermeasures of Imported Medical Vector Biology Nationwide

The research and prevention and control of imported medical media is one of the important topics in the field of public health. With the acceleration of globalization, the transnational spread of various medical media organisms through travel, trade and population migration has become a major challenge for public health. This paper summarizes the research status and main problems of imported medical media in China, and focuses on the countermeasures and prevention and control measures, including strengthening monitoring and early warning, improving quarantine, and strengthening international cooperation. It is hoped that the discussion of this paper can provide reference for the research and prevention and control of imported medical media in China.

Differences in Salmonella Typhimurium infection and excretion among laboratory and field strains of the German cockroach suggest a genomic basis for vector competence

The German cockroach, Blattella germanica, can be a vector of human enteric bacterial pathogens, including Salmonella enterica serovar Typhimurium (S. Typhimurium). Transmission of such pathogens by cockroaches has largely been considered a passive mechanical process, but recent studies have argued against this dogma by demonstrating bacterial proliferation within the cockroach gut and the necessity of specific bacterial genes for successful transmission in the feces, revealing unappreciated biological complexity in the vector-pathogen relationship between cockroaches and S. Typhimurium. However, the influence of naturally occurring variation among cockroach populations on pathogen infection and dissemination has not been investigated. Thus, this study aimed to examine whether distinct strains of B. germanica exhibit differences in their ability to become infected by and disseminate S. Typhimurium. We performed controlled infections of one long-term laboratory strain and three recently field-collected strains reared under identical conditions, then compared bacterial loads in the body and excreta of individual insects. Separately, we also compared rates of necrophagy, a behavior known to contribute to the horizontal spread of S. Typhimurium among cockroaches. Our data show significant differences in infection susceptibility, pathogen shedding in the excreta, and necrophagy between laboratory and field strains as well as between some field strains. These observations represent the first evidence that genomic variation among cockroach populations may influence their ability to become infected by and disseminate pathogens, providing further support for the hypothesis that German cockroaches are active biological vectors rather than passive mechanical vectors of S. Typhimurium. Additional studies are needed to identify the genomic drivers of vector competence for S. Typhimurium in B. germanica.