Number Of Vector-borne Diseases Research Articles

Burden, knowledge and perception of lymphatic filariasis in resource - poor communities in north central Nigeria.

A number of vector-borne diseases are known to affect humans in tropical and sub-tropical regions of the world. Lymphatic filariasis is one of such debilitating disease caused by a nematode, Wuchereria bancrofti. The present study assessed the prevalence of lymphatic filariasis by screening individuals with filariasis test strip and clinical examination. A sample of 765 consenting individuals were screened for filarial antigenemia using filariasis test strip and clinical examination and interviewed for knowledge and perception of filariasis using a structured questionnaire. Overall antigenemia prevalence was 8.8% and the disease prevalence varied among villages with Shonga (16.7%) having the highest and Tada (1.6%) the least infected.In relation to age group, 40-49years had the highest (49.3%) while 0-9 years did not record any infection. Among the respondents infected, a greater number (43.3%) believed that the disease was caused by stepping on charm, 45.4% of those unaffected also believed in the same cause. A greater number of the respondents (28.4%) believed that avoiding sexual intercourse with affected individuals can help prevent the disease. A majority(67.2%) of the study participant had a misconception about its preventive measure. Misconceptions on the preventive measures included sacrifice to appease the gods and avoiding sexual intercourse with affected individuals. This study showed filarial antigenemia was above the threshold of 2% in the study area with misconception on the disease transmission and therefore this area warrants strategies to prevent transmission.

739. Self-Reported Prevalence of Insect Bites During International Travel

BackgroundVector borne diseases are responsible for almost one fifth of global infectious disease burden. International travelers are at risk for potentially life-threatening conditions when visiting areas with endemic vector borne disease, but this risk can be mitigated when proper insect precautions are taken. This study sought to evaluate the prevalence of insect precaution use and subsequent insect bites among Utah travelers who have attended pre-travel consultations. MethodsA cross-sectional study at the University of Utah and Salt Lake County travel clinics was analyzed. Descriptive statistics and multivariable logistic regression were used to explore factors associated with insect repellant use, and reporting bug bites despite insect repellant use.ResultsA total of 463 individuals completed the survey and were included in our analytic sample. The majority of respondents (80%) reported using insect repellent, and close to half (45%) reported bug bites. Insect repellent use was positively associated with visiting rural/countryside (OR 2.78, 95% CI 1.50 – 5.15), and traveling to South East Asia (OR 3.16, 95% CI 1.40 – 7.26), or Americas regions (OR 3.34, 95% CI 1.45 – 7.92). Being of male gender (OR 0.37, 95% CI 0.21 – 0.64) or traveling to high altitude locations (OR 0.37, 95% CI 0.18 – 0.74) was negatively associated with using insect repellent. Longer trip duration (OR 1.01, 95% CI 1.00 – 1.02) was positively associated with reporting insect bites, while male gender (OR 0.51, 95% CI 0.33 – 0.80), older age (OR 0.96, 95% CI 0.95 – 0.98), and having an advanced degree (OR 0.47, 95% CI 0.22 – 0.99) were negatively associated.Estimated Risk Factors of Insect Bites and Insect Repellent Use Characteristics of international travelers were self-reported in a cross-sectional study. Use of insect repellent and reporting bug bites despite repellant use was examined through multivariate logistic regression and used to calculate odds ratios and 95% confidence intervals. Due to multicollinearity and data skewness, the following variables were omitted from the insect repellent model: Accommodation: Hotel/other enclosed structure, Location: European, Location: and Western Pacific. Reference categories are Gender: Female, Education: High school diploma/GED or less, Group size: 1 (Traveled alone), Location type: Urban, and Malaria region: No. All other categories are not mutually exclusive and evaluated as separate binary variables.ConclusionWe show that gender, age, trip duration, and education level were associated with self-reported bug bites during travel abroad. Given the number of vector-borne diseases affecting health of travelers, our findings will contribute towards strategies to advise travelers for disease prevention.Disclosures All Authors: No reported disclosures

Livestock Protective Fencing (LPF) to protect dairy cattle against vectors in Serbia - project processes and methodology

Lumpy skin disease (LSD) is among a number of vector-borne diseases (VBDs) threatening the Balkans and therefore, preventing feeding of insects on cattle would reduce the spread of VBDs. In order to test the efficiency of Livestock Protective Fences (LPF) in the protection of dairy cattle from insect bites, a case-control study was conducted, in the districts of Nisava, Pirot and Pcinja, Southern Serbia. It consisted in comparing the number of biting flies collected within time, between 10 farms protected with LPF and 10 non protected ones. The insects were collected using two types of traps; the monoconical Vavoua trap set outside in between forested areas or rivers and the actual farm, and the BGsentinel trap baited with CO2, placed in proximity of the cattle but outside the stable. Vectors were collected every 15 days for 48 hours from May to October 2018 and kept in vials containing 70% of ethanol. Catches per trap were separately stored and for each trap, insects were classified according to species and sex and then counted. Data on milk parameters were analyzed separately, on data collected within protected farms, before and after the LPF deployment, and on data without protection at all. It was not possible to detect a direct impact of LPF on vector densities but the number of bacteria colonies (CFU) values were reduced. Some corrections/adaption in the methodology used may lead to better impact.

The flea reproductive break point — what it is and how it is pivotal for successful flea control

The cat flea Ctenocephalides felis is a source of revulsion, distress and irritation for pet owners worldwide. In addition, C. felis can also cause flea allergic dermatitis (FAD) in susceptible pets as well as significant bite reactions in people. This in combination, with the cat flea’s capability of transmitting a number of vector-borne diseases, makes control of this parasite vital. Veterinary nurses play a key role in educating clients about fleas and putting practical control programmes in place. A crucial component of this is the flea reproductive break point, which if not considered will lead to failure of flea control programmes. This article considers flea control, and the importance of the reproductive break point in ensuring that flea control strategies are successful.

POTENTIAL EXPANSION OF TROPICAL VIRUSES IN SERBIA AND EUROPE

The current, hot topic is the risk of introducing new vector-borne diseases and harmful ectoparasites into Europe, or of the geographic extension of the existing ones. There are many doubts that global warming affects the transfer of a number of vectorborne diseases. Special emphasis was placed on spreading the Lyme disease, tick-borne encephalitis, West Nile fever and leishmaniasis, the recurrence of malaria and dengue fever. Climate models predict a 2-5oC temperature increase and a significant increase in rainfall in Europe in the following years. However, non-environmental variables such as socio-economic situation and agriculture should be considered. The main problem can be expected when new viruses emerge. As they change, their mutations can enter into the population and thus have “the greater potential” for the spread of the epidemic. The control network of the health system in our country and in Europe is very dense, and the outbreak of the virus can be always registered, giving the authorities enough time to take measures. Although modeling studies indicate that climate change could increase the risk of transmission of vector -transmitted diseases in Serbia and Europe, historical analyses indicate that, at least for malaria, socio-economic conditions in combination with effective surveillance and early treatment are likely to prevent further spread, which is the main task of the Public Health Institutes. Tropical medicine experts said that the so-called supervirus causes mutations of the virus, and represents the greatest danger for human population. The circumstances that allow such a development already exist, an additional climate change is not necessary. The challenge for future research is the mechanism of tropical viruses and their persistence in endemic foci in temperate climate area in Europe. Acta Medica Medianae 2015;54(4):64-71.

Reduced Prevalence of Malaria Infection in Children Living in Houses with Window Screening or Closed Eaves on Bioko Island, Equatorial Guinea

BackgroundPrevious studies demonstrated that fewer mosquitoes enter houses which are screened or have closed eaves. There is little evidence about the effect on malaria infection in humans that changes in house construction may have. This study examines the impact of protective housing improvements on malaria infection on Bioko Island.Methodology/Principal FindingsData from the annual malaria indicator surveys between 2009 and 2012 were used to assess trends in housing characteristics and their effect on RDT confirmed malaria infection in household members. Odds ratios were adjusted for socio-economic status of the household.22726 children between the ages of 2 and 14 years were tested for P. falciparum. Prevalence of infection in those living in houses with open eaves was 23.0% compared to 18.8% for those living in houses with closed eaves (OR = 0.81, 95% CI 0.67 - 0.98). The prevalence of infection for children in screened houses was 9.1% versus 20.1% for those living in unscreened houses (OR = 0.44, 95% CI 0.27 - 0.71). The proportion of houses with closed eaves increased from 66.0% in 2009 to 74.3% in 2012 (test for trend p = 0.01). The proportion of screened houses remained unchanged over time at 1.3%.Conclusion/SignificanceAs a malaria control intervention, house modification has the advantages that it is not affected by the growing threat of insecticide resistance; it protects all household members equally and at all times while indoors; and it offers protection against a number of vector borne diseases. The study provides evidence in support of efforts to regulate or encourage housing improvements which impede vector access into residences as part of an integrated vector control approach to complement existing measures which have been only partially successful in reducing malaria transmission in some parts of Bioko.

Generic Insect Repellent Detector from the Fruit Fly Drosophila melanogaster

BackgroundInsect repellents are prophylactic tools against a number of vector-borne diseases. There is growing demand for repellents outperforming DEET in cost and safety, but with the current technologies R&D of a new product takes almost 10 years, with a prohibitive cost of $30 million dollar in part due to the demand for large-scale synthesis of thousands of test compounds of which only 1 may reach the market. R&D could be expedited and cost dramatically reduced with a molecular/physiological target to streamline putative repellents for final efficacy and toxicological tests.MethodologyUsing olfactory-based choice assay we show here that the fruit fly is repelled by not only DEET, but also IR3535 and picaridin thus suggesting they might have “generic repellent detector(s),” which may be of practical applications in new repellent screenings. We performed single unit recordings from all olfactory sensilla in the antennae and maxillary palps. Although the ab3A neuron in the wild type flies responded to picaridin, it was unresponsive to DEET and IR3535. By contrast, a neuron housed in the palp basiconic sensilla pb1 responded to DEET, IR3535, and picaridin, with apparent sensitivity higher than that of the DEET detectors in the mosquitoes Culex quinquefasciatus and Aedes aegypti. DmOr42a was transplanted from pb1 to the “empty neuron” and showed to be sensitive to the three insect repellents.ConclusionsFor the first time we have demonstrated that the fruit fly avoids not only DEET but also IR3535 and picaridin, and identified an olfactory receptor neuron (ORN), which is sensitive to these three major insect repellents. We have also identified the insect repellent-sensitive receptor, DmOr42a. This generic detector fulfils the requirements for a simplified bioassay for early screening of test insect repellents.

Launching the first postgraduate diploma in medical entomology and disease vector control in Pakistan

The Health Services Academy has launched a 12-month postgraduate diploma course in medical entomology and disease vector control. The objective is to create a core of experts trained to prevent and control vector-borne diseases. The course is a response to the serious health and socioeconomic burden caused by a number of vector-borne diseases in Pakistan. The persistence, emergence and re-emergence of these diseases is mainly attributed to the scarcity of trained vector-control experts. The training course attempts to fill the gap in trained manpower and thus reduce the morbidity and mortality due to these diseases, resulting in incremental gains to public health. This paper aims to outline the steps taken to establish the course and the perceived challenges to be addressed in order to sustain its future implementation.

Arthropod borne diseases in Italy: from a neglected matter to an emerging health problem

In medical entomology, "Arthropod Borne Diseases", or "Vector Borne Diseases" (VBD) are intended as a group of human and animal infections caused by different pathogen organisms (protozoa, helminths, bacteria and viruses) transmitted by the bite of a bloodsucking insect or arachnid. It is commonly known that the infectious diseases transmitted by Arthropods are mainly affecting tropical and subtropical countries, nevertheless some of them were or are still common also in the northern hemisphere, where they are usually maintained under control. VBD still represent some of the most important public health problems in the endemic areas but are becoming source of concern for developed countries too. Since the last decades of the past century, a number of VBD has been spreading geographically, being recorded for the first time in areas outside their original range. This phenomenon is strictly related to the peculiar epidemiological characteristics of these diseases, that are considered the most susceptible to climatic, environmental and socioeconomic changes. This article is a short overview of the VBD endemic and emerging in Italy. The possibility that some exotic vectors and/or pathogens could be introduced and become established in Italy is also discussed.

Monitoring trypanosomiasis in space and time.

The paper examines the possible contributions to be made by Geographic Information Systems (GIS) to studies on human and animal trypanosomiasis in Africa. The epidemiological characteristics of trypanosomiasis are reviewed in the light of the formula for the basic reproductive rate or number of vector-borne diseases. The paper then describes how important biological characteristics of the vectors of trypanosomiasis in West Africa may be monitored using data from the NOAA series of meteorological satellites. This will lead to an understanding of the spatial distribution of both vectors and disease. An alternative, statistical approach to understanding the spatial distribution of tsetse, based on linear discriminant analysis, is illustrated with the example of Glossina morsitans in Zimbabwe, Kenya and Tanzania. In the case of Zimbabwe, a single climatic variable, the maximum of the mean monthly temperature, correctly predicts the pre-rinderpest distribution of tsetse over 82% of the country; additional climatic and vegetation variables do not improve considerably on this figure. In the cases of Kenya and Tanzania, however, another variable, the maximum of the mean monthly Normalized Difference Vegetation Index, is the single most important variable, giving correct predictions over 69% of the area; the other climatic and vegetation variables improve this to 82% overall. Such statistical analyses can guide field work towards the correct biological interpretation of the distributional limits of vectors and may also be used to make predictions about the impact of global change on vector ranges. Examples are given of the areas of Zimbabwe which would become climatically suitable for tsetse given mean temperature increases of 1, 2 and 3 degrees Centigrade. Five possible causes for sleeping sickness outbreaks are given, illustrated by the analysis of field data or from the output of mathematical models. One cause is abiotic (variation in rainfall), three are biotic (variation in vectorial potential, host immunity, or parasite virulence) and one is historical (the impact of explorers, colonizers and dictators). The implications for disease monitoring, in order to anticipate sleeping sickness outbreaks, are briefly discussed. It is concluded that present data are inadequate to distinguish between these hypotheses. The idea that sleeping sickness outbreaks are periodic (i.e. cyclical) is only barely supported by hard data. Hence it is even difficult to conclude whether the major cause of sleeping sickness outbreaks is biotic (which, in model situations, tends to produce cyclical epidemics) or abiotic.(ABSTRACT TRUNCATED AT 400 WORDS)

Highlights in Medical Entomology in 1974

The incidence of a number of vector-borne diseases has increased in 1974 and represents a cause for concern by public health workers. The rise in the number of cases of Rocky Mountain spotted fever (774 cases and 38 deaths) ; the 8 cases of plague, with one death; the outbreak of St. Louis encephalitis in the Memphis, Tenn., area with at least 44 cases; and the single-focus epidemic of tick-borne relapsing fever originating in the North Rim area of the Grand Canyon National Park (which occurred in 1973 but was reported in 1974) are notable. Another problem of concern is the rise in number of cases of head lice infestations, particularly in school children.