Molecular analysis of photic inhibition of blood-feeding in Anopheles gambiae

<p>Abstract</p> <p>Background</p> <p><it>Anopheles gambiae </it>mosquitoes exhibit an endophilic, nocturnal blood feeding behavior. Despite the importance of light as a regulator of malaria transmission, our knowledge on the molecular interactions between environmental cues, the circadian oscillators and the host seeking and feeding systems of the <it>Anopheles </it>mosquitoes is limited.</p> <p>Results</p> <p>In the present study, we show that the blood feeding behavior of mosquitoes is under circadian control and can be modulated by light pulses, both in a clock dependent and in an independent manner. Short light pulses (~2–5 min) in the dark phase can inhibit the blood-feeding propensity of mosquitoes momentarily in a clock independent manner, while longer durations of light stimulation (~1–2 h) can induce a phase advance in blood-feeding propensity in a clock dependent manner. The temporary feeding inhibition after short light pulses may reflect a masking effect of light, an unknown mechanism which is known to superimpose on the true circadian regulation. Nonetheless, the shorter light pulses resulted in the differential regulation of a variety of genes including those implicated in the circadian control, suggesting that light induced masking effects also involve clock components. Light pulses (both short and long) also regulated genes implicated in feeding as well as different physiological processes like metabolism, transport, immunity and protease digestions. RNAi-mediated gene silencing assays of the light pulse regulated circadian factors <it>timeless</it>, <it>cryptochrome </it>and three <it>takeout </it>homologues significantly up-regulated the mosquito's blood-feeding propensity. In contrast, gene silencing of light pulse regulated olfactory factors down-regulated the mosquito's propensity to feed on blood.</p> <p>Conclusion</p> <p>Our study show that the mosquito's feeding behavior is under circadian control. Long and short light pulses can induce inhibition of blood-feeding through circadian and unknown mechanisms, respectively, that involve the chemosensory system.</p

The history of malarial fever and contributions to it Ronald Ross.

Thesis (M.A.)--Boston Universit

Dynamic analysis of a needle insertion for soft materials: Arbitrary Lagrangian-Eulerian-based three-dimensional finite element analysis

Background: Our goal was to develop a three-dimensional finite element model that enables dynamic analysis of needle insertion for soft materials. To demonstrate large deformation and fracture, we used the arbitrary Lagrangian-Eulerian (ALE) method for fluid analysis. We performed ALE-based finite element analysis for 3% agar gel and three types of copper needle with bevel tips. Methods: To evaluate simulation results, we compared the needle deflection and insertion force with corresponding experimental results acquired with a uniaxial manipulator. We studied the shear stress distribution of agar gel on various time scales. Results: For 30°, 45°, and 60°, differences in deflections of each needle between both sets of results were 2.424, 2.981, and 3.737. mm, respectively. For the insertion force, there was no significant difference for mismatching area error (p<0.05) between simulation and experimental results. Conclusions: Our results have the potential to be a stepping stone to develop pre-operative surgical planning to estimate an optimal needle insertion path for MR image-guided microwave coagulation therapy and for analyzing large deformation and fracture in biological tissues. © 2014 Elsevier Ltd.Yamaguchi S., Tsutsui K., Satake K., et al. Dynamic analysis of a needle insertion for soft materials: Arbitrary Lagrangian-Eulerian-based three-dimensional finite element analysis. Computers in Biology and Medicine 53, 42 (2014); https://doi.org/10.1016/j.compbiomed.2014.07.012

Contemporary and Ancient Review of Mosquitoes - A Review

Indian system of medicine plays an important part in health care system all over India. There are numerous allusions to mosquitoes in Indian writings from the Vedic era. The Atharvaveda makes special reference of mosquito shape, habitat, many varieties, behaviour, and even their presence throughout the year. The 67 different forms of Keet and their genesis were documented by Acharya Susruta in Kalpasthana, while Keet Visha describes five different types of Mashak in which Parvatiya Mashak is the most hazardous to people. There is also Mashak description In Charaka Samhita of chapter Visha Chikitsa. Numerous mosquito species have been identified in contemporary science. Mosquitoes are the most important group of blood sucking insects causing nuisance diseases to humans and other animals.&nbsp; It follows that our ancestors' seers or philosophers were already aware of this

The Bionomics of the Culicidae of the Dallas Area

Little work has been done on Texan mosquitoes. In 1922 Dyar listed 43 species from Texas, 10 of which were recorded from near Dallas. Cushing (1934) listed the mosquitoes of Brazos County. McGregor & Eads (1934) in their work on the mosquitoes of Texas, divided the State into 17 approximately equal areas. They gave a total list of 54 species, of which 19 were reported from the area that included Dallas County. Fisk & LeVan (1941) published notes on the mosquitoes of Brownsville. The State Health Department of Texas published (1944) a booklet, The Mosquitoes of Texas , which is the most complete work on the mosquitoes of the State. It included keys and descriptions, as well as ecological and distributional notes on the 75 species listed. O\u27Neill, Ogden, & Eyles (1944) supplemented McGregor & Eads\u27 list with nine species. Hollingsworth (1948) listed the mosquitoes from the neighborhood of Nacogdoches

Migration - utopia or myopia?

Peter Osborne spent a sabbatical in northern America and was surprised that so many scientists and students stated that caribou migration was largely the result of mosquito pressure. He failed however to find any documented evidence of this claim although he was constantly confronted by the well known &laquo;facts&raquo; that mosquitoes had been observed to drive caribou crazy and even kill juveniles. The issue Osborne wishes to focus is that an experimentally unsubstantiated anthropomorphism appears to have become critical evidence in support of a theory. A recent article in Nature (393, 511-513, 1998) devoted to the uses of 'science in fiction' to stimulate thought and discussion about aspects of academia encouraged him to write the following comment in the form of a parody of ancient Greek dialogues

Prevalence of Wuchereria Bancrofti Antigenemia and Associated Factors Among Children of School Age Born After Initiation of Mass Drug Administration with ivermectin and albendazole in Rufiji district, Tanzania

The National Lymphatic Filariasis (LF) Elimination Programme use Ivermectin and Albendazole mass drug administration (MDA) for the control of LF. Screening children of school age has successfully been used for mapping geographical distribution of LF worldwide. The implementation of MDA for LF in Rufiji district started in 2002 and up to 2011, nine rounds had been administered. The prevalence of LF after MDA was not known, thus this study aimed to screen children born during the period of programme implementation in order to assess the transmission status. This study aimed to determine the prevalence of Wuchereria bancrofti antigenaemia and associated factors among school age children born after the initiation of mass drug administration in Rufiji District. A descriptive cross sectional study involving heads of household and school age children born during the implementation of the MDA program was carried out in Rufiji district. Blood samples were drawn from 413 standard one pupils. CFA was tested from the blood sample by using ICT cards in order to establish prevalence of W.bancrofti. A total of 270 heads of household were interviewed so as to establish the relationship between coverage, knowledge and prevalence of bancroftian filariasis. A total of 413 children between the age of 6 and 9 years were tested for CFA, 59 (14.3%) being positive for Wuchereria bancrofti. Two thirds (66.8%) of the children did not take ivermectin and albendazole during the 2011 MDA. Prevalence of Wuchereria bancrofti was lower in younger children (6.4%) than older ones (40.4%). Prevalence of Wuchereria bancrofti was significantly high (70.8%) in children who did not swallow tablets than in those who swallowed the tablets (29.2%), (P = 0.015). Though the larger majority of households (97.0%) had heard of the disease, only 57.0% knew it was transmitted by mosquitoes, while 56.4% had no adequate knowledge on the disease and proper use of drugs. The study also found out that respondents have different cultural beliefs on the cause of the disease and there was improper drug distribution during MDA. The prevalence of Wuchereria bancrofti in Rufiji is still high despite the ongoing elimination programme. Poor knowledge on the disease transmission, cultural beliefs and improper drug distribution were associated with the sustained high prevalence.\u

Effect of discriminative plant-sugar feeding on the survival and fecundity of Anopheles gambiae

<p>Abstract</p> <p>Background</p> <p>A previous study showed for <it>Anopheles gambiae s.s</it>. a gradation of feeding preference on common plant species growing in a malaria holoendemic area in western Kenya. The present follow-up study determines whether there is a relationship between the mosquito's preferences and its survival and fecundity.</p> <p>Methods</p> <p>Groups of mosquitoes were separately given <it>ad libitum </it>opportunity to feed on five of the more preferred plant species (<it>Hamelia patens</it>, <it>Parthenium hysterophorus</it>, <it>Ricinus communis</it>, <it>Senna didymobotrya</it>, and <it>Tecoma stans</it>) and one of the less preferred species (<it>Lantana camara</it>). The mosquitoes were monitored daily for survival. Sugar solution (glucose 6%) and water were used as controls. In addition, the fecundity of mosquitoes on each plant after (i) only one blood meal (number of eggs oviposited), and (ii) after three consecutive blood meals (proportion of females ovipositing, number of eggs oviposited and hatchability of eggs), was determined. The composition and concentration of sugar in the fed-on parts of each plant species were determined using gas chromatography. Using SAS statistical package, tests for significant difference of the fitness values between mosquitoes exposed to different plant species were conducted.</p> <p>Results and Conclusion</p> <p><it>Anopheles gambiae </it>that had fed on four of the five more preferred plant species (<it>T. stans</it>, <it>S. didymobotrya</it>, <it>R. communis </it>and <it>H. patens</it>, but not <it>P. hysterophorus</it>) lived longer and laid more eggs after one blood meal, when compared with <it>An. gambiae </it>that had fed on the least preferred plant species <it>L. camara</it>. When given three consecutive blood-meals, the percentage of females that oviposited, but not the number of eggs laid, was significantly higher for mosquitoes that had previously fed on the four more preferred plant species. Total sugar concentration in the preferred plant parts was significantly correlated with survival and with the proportion of females that laid eggs. This effect was associated mainly with three sugar types, namely glucose, fructose, and gulose. Except for <it>P. hysterophorus</it>, the results suggest that feeding by mosquitoes on preferred plant species under natural conditions results in higher fitness-related benefits, and that the sugar content in preferred plant parts is largely responsible for these effects.</p

Vector competence experiments with Rocio virus and three mosquito species from the epidemic zone in Brazil

First-generation progeny of field-collected Psorophora ferox, Aedes scapularis, and Aedes serratus from the Rocio encephalitis epidemic zone in S.Paulo State, Brazil, were tested for vector competency in the laboratory. Psorophora ferox and Ae. scapularis are susceptible to per os infection with Rocio virus and can transmit the virus by bite following a suitable incubation period. Oral ID50S for the two species (10(4.1) and 10(4.3) Vero cell plaque forming units, respectively) did not differ significantly. Infection rates in Ae. serratus never exceeded 36%, and, consequently, an ID50 could not be calculated for this species. It is unlikely that Ae. serratus is an epidemiologically important vector of Rocio virus. The utility of an in vitro feeding technique for demonstrating virus transmission by infected mosquitoes and difficulties encountered in working with uncolonized progeny of field-collected mosquitoes are discussed.Em condições de laboratório procedeu-se a ensaios visando testar a capacidade vetora para o virus Rocio, da primeira geração de Psorophora ferox, Aedes scapularis e Aedes serratus obtida a partir de especimens coletados na região epidêmica do Estado de São Paulo, Brasil. Psorophora ferox e Aedes scapularis revelaram-se suscetíveis à infecção por via oral e capazes de transmitir o vírus mediante a picada após período adequado de incubação. Para as duas espécies, as ID50 orais não diferiram significativamente. Em Ae. serratus as taxas de infecção nunca ultrapassaram os 36,0% o que impossibilitou o cálculo da ID50 para essa espécie. É improvável que Ae. serratus seja vetor epidemiológicamente importante do vírus Rocio. Discute-se a utilidade da técnica de alimentação "in vitro" para demonstrar a transmissão por mosquitos infectados, e também as dificuldades encontradas ao trabalhar com gerações não colonizadas originárias de especimens coletados no campo

Mosquito 101

Training Module 1: Basics of Mosquito biology, ecology, physiology, and behavior Training Module 2: Aedes aegypti Training Module 3: Anopheles quadrimaculatus Training Module 4: Culex quinquefasciatus Quizzes Reference