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How Biological Vectors Are Responsible For Malaria

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Acute Communicable Disease Control

Vector biology and malaria transmission

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Acute Communicable Disease Control
  • Vector-Borne Disease: Disease that results from an infection transmitted to humans and other animals by blood-feeding anthropods, such as mosquitoes, ticks, and fleas. Examples of vector-borne diseases include Dengue fever, West Nile Virus, Lyme disease, and malaria.
  • Zoonotic Disease: a disease that can be transmitted from animals to people or, more specifically, a disease that normally exists in animals but that can infect humans. There are multitudes of zoonotic diseases.

Which Is Faster Vector Or Array

A std::vector can never be faster than an array, as it has an array as one of its data members. But the difference in run-time speed is slim and absent in any non-trivial program. A second reason for this myth to persist is when comparing arrays and std::vector in debug mode.

Where We Are Today

Vector biology, broadly defined, is the science devoted to studying insects that transmit pathogens, their contact with humans, and their interaction with the disease-causing organisms. In the case of malaria, the is the mosquito and the disease-causing organism is the malaria parasite. Humans and anopheline mosquitoes are both considered to be the parasite’s hosts.

One of the primary goals of biology in malaria research is to promote a better understanding of the disease cycle that will facilitate more effectively targeted control strategies. The vast majority of successful antimalaria campaigns have relied heavily on vector control.

The distribution of malaria within human populations is linked closely to site-specific characteristics of populations. Within any given area, there are usually fewer than five vector species, although the biology of each species is unique in many respects, including the sites where larvae develop, adult mosquito behavior , susceptibility to Plasmodium parasites, and the ability to transmit these parasites.

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Malaria Transmission And Primary Vectors In Mainland Southeast Asia

As members of a species complex usually exhibit significant behavioral differences, understanding the biological, behavioral three main malaria vectors are recognized on the sea mainland: Information on vector control interventions used to reduce malaria’s impact including larval control and other vector control interventions. The crude associations between malaria and climatic factors were initially examined graphically using restricted cubic splines figure 3 shows the maximum lagged effects of t max, t min and average relative humidity on malaria for the nine selected cities. Malaria entomology and vector control.

Larval Control And Other Vector Control Interventions

CDC

Larval Control

Interventions targeting the larval stages of the mosquito have been used effectively for decades, but their effectiveness varies widely from species to species. In general, if habitats are large and amenable to environmental modification, the intervention is effective, but if habitats are small, widely dispersed, and transient the intervention is less effective.

Anopheles gambiae, one of the primary vectors of malaria in Africa, breeds in numerous small pools of water that form due to rainfall. The larvae develop within a few days, escaping their aquatic environment before it dries out. It is difficult, if not impossible, to predict when and where the breeding sites will form, and to find and treat them before the adults emerge. Therefore, larval mosquito control for the prevention of malaria in Africa has not been attempted on a large scale. It may, however, be appropriate for specific settings such as urban environments or desert fringe areas where habitats are more stable and predictable. In contrast, in Southeast Asia, Europe and the Americas, larval control has proven extremely effective.

Larval control may be implemented through environmental modification draining and filling or through use of larvacides. Though biological control using fish is often used, evidence for its effectiveness is limited.

Chemical Larviciding

Biological Control

Other Vector Control Interventions

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Counterfeit And Substandard Drugs

Sophisticated counterfeits have been found in several Asian countries such as Cambodia,China,Indonesia, Laos, Thailand, and Vietnam, and are a major cause of avoidable death in those countries. The WHO said that studies indicate that up to 40% of artesunate-based malaria medications are counterfeit, especially in the Greater Mekong region. They have established a rapid alert system to rapidly report information about counterfeit drugs to relevant authorities in participating countries. There is no reliable way for doctors or lay people to detect counterfeit drugs without help from a laboratory. Companies are attempting to combat the persistence of counterfeit drugs by using new technology to provide security from source to distribution.

Another clinical and public health concern is the proliferation of substandard antimalarial medicines resulting from inappropriate concentration of ingredients, contamination with other drugs or toxic impurities, poor quality ingredients, poor stability and inadequate packaging. A 2012 study demonstrated that roughly one-third of antimalarial medications in Southeast Asia and Sub-Saharan Africa failed chemical analysis, packaging analysis, or were falsified.

Sand Flys And Leishmania

From Peter and Gilles

Sand flies are the vectors for Leishmania as well as some bacterial and viral diseases. Adult sand flies are about 2 mm in length and characterized by hair bodies and wings . Genera of sand flies fall into two groups: Phlebotomus and Sergentomyia found in the Eastern hemisphere , and Lutzomyia, Brumptomyia and Warileya in the Western hemisphere . In general, the Old World sand fly species live in desert or semi-arid ecosystems and the New World species are forest dwelling. Some of the Old World species will breed in peridomestic situations and enter human habitations, whereas disease transmission in the New World is associated with humans living or working near the forest.

The sand flies responsible for the transmission of leishmaniasis are Phlebotomus and Lutzomyia in the Old and New Worlds, respectively. The spatial distribution of leishmaniasis and other sand fly transmitted diseases tends to be patchy due to the limit flying range of the sand fly. Their flying is often described as ‘hopping’, characterized by short bursts of flights separated by a couple of seconds of rest. Sand flies have a short flight range and are usually found within a dozen meters of a breeding site.

There are also factors within the sandfly saliva which potentiate the infectivity of Leishmania for the vertebrate host. Some of these salivary gland compounds have immunosuppressive activities against lymphocytes and macrophages which may explain the potentiation.

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Is Biological Larviciding Against Malaria A Starting Point For Integrated Multi

  • Roles Conceptualization, Formal analysis, Software, Writing original draft

    Affiliation Institute for Global Health, University Hospital Heidelberg, Heidelberg, Germany

  • Roles Writing original draft, Writing review & editing

    Affiliation Centre de Recherche Entomologique de Cotonou , Cotonou, Benin

  • Roles Conceptualization, Methodology, Supervision, Writing original draft, Writing review & editing

    Affiliation Institute of Zoology, University of Cologne, Cologne, Germany

  • Roles Conceptualization, Data curation, Investigation, Supervision, Writing original draft

    Affiliation Centre de Recherche en Santé de Nouna, Nouna, Burkina Faso

Biology And Bionomics Of Major Malaria Vector Species And Their Sibling Species In Different Ecosystems

Parasitology 002 a Vectors Vector Borne diseases Biological Mechanical Mosquito malaria housefly

Anopheles sundaicus is now found only in Andaman and Nicobar Islands and was not reported from the mainland after its last report in 197475 from South 24 Parganas district in West Bengal . Prior to its disappearance from mainland, this species was reported from Andhra Pradesh, Odisha and West Bengal . This is a species complex, and only one species, species D was found in the islands . It has a low preference to bite humans, with HBI of 0.025, but in exclusive human dwelling collections, HBI was 0.18 . It was collected indoors from both human dwellings and cattle sheds, and also from outdoors. Exophagy and bimodal biting activity with peak biting around 23.00;h and the second peak around 02.00;h were observed . In a recent study conducted in the Andaman and Nicobar Islands, An. sundaicus was found positive for P. knowlesi .

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Engineering Mosquitoes So That They Cannot Transmit Disease

Most diseases that are transmitted by mosquitoes go through a period of replication in the vector, which can thus be thought of as a secondary host. To do this requires an intimate relationship with the insect; for example, in the case of malaria, the mobile zygote must penetrate the gut wall and form a cyst and then produce forms that colonise the salivary gland. The pathogen is thus exposed to the mosquito’s humoral and cellular immune system and requires a variety of cell and tissue recognition factors to orchestrate successful transmission. Strains of mosquitoes are known that are very poor at transmitting malaria, and these presumably either attack the pathogen or lack factors essential for Plasmodium.

Mass release of engineered mosquitoes may have a role in the targeted elimination of some disease or vector populations but is unlikely to be a viable solution for disease control over large areas, particular in the lowest-income countries. An alternative is to spread the new gene or construct through a population using a genetic drive mechanism.

Addressing Malaria Control Elimination And Eradication From A Biomedical Research Perspective

Malaria, as a disease and public health challenge, reflects an extremely complex set of interactions between the parasite, the human host, and the vectors responsible for transmission . Environmental, social, economic, and behavioral factors enable and foster these interactions and, thus, support perpetuation of malaria as long as the life cycle of the parasite remains intact. In principle, any intervention that achieves a complete blockage at any point in the life cycle of the parasite would effectively interrupt transmission and facilitate eradication efforts. To date, however, no single intervention with such complete activity has been identified, and until that occurs, multiple interventions operating at various points in the life cycle of the malaria parasite will be needed to maximally inhibit progression through the life cycle and prevent transmission

The life cycle of malaria parasites. A Bottleneck in transmission of malaria from mosquito to man. B Bottleneck in transmission of malaria from man to mosquito. rbc, red blood cell

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Is Std : : Vector Efficient

Efficient way of using std::vector For example, std::list or std::map tends to allocate many small objects and dynamic allocation is a time-consuming operation. But std::vector is just a wrapper over a dynamically allocated array that also remembers its size and can reallocate when you add new elements.

Opportunities For New Tools For The Control Of Disease Vectors

PPT

Recent years have seen dramatic reductions in the burden of malaria worldwide. The decline is largely attributable to the broad-scale use of long lasting insecticide treated nets and indoor residual sprays against adult mosquitoes . The success of these insecticide-based interventions represents a foundational step in the global agenda to eliminate malaria. However, the current control tools alone are likely insufficient to eliminate malaria in many settings, even if their use could be intensified further . Additionally, there is a growing problem of insecticide resistance that could render existing tools ineffective and potentially lead to a reversal of recent gains .

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Biological Control Of Mosquito Vectors

Past Present and Future. This is particularly important for the control of mosquito-borne arboviruses which normally do not have specific antiviral therapies available.

Mosquito Life Cycle For Education Download A Free Preview Or High Quality Adobe Illustrator Ai Eps Pdf And High Res Life Cycles Mosquito Life Cycle Mosquito

Biological control is the use of living organism to control a vector.

Biological control of mosquito vectors. Likewise mosquito fish including Gambusia affinis have largely been ineffective. Biological controls with predators of larval mosquito vectors have historically focused almost exclusively on insectivorous animals with few studies examining predatory plants as potential larvacidal agents. Biological control methods or strategies against the vectors are safe and environmental-friendly.

Unfortunately no treatment in the form of vaccines or drugs is available for most of these diseases and vector control is still the main form of prevention. Using fish that eat mosquito larvae the use cat fish to eat up mosquito larve in pond can eradicate the mosquito population or reducing breeding rates by introducing sterilized male tsetse flies have been shown to control vector populations and reduce infection risks. A review of the role of sh as biological control agents of disease vector mosquitoes in mangrove forests.

Biological control methods are very important in protecting the public from mosquitoes.

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Innovative Methods For Malaria Control

Antimosquito Vaccines

Unlike vaccines directed against the malaria parasite, an antimosquito vaccine would be effective against all Plasmodium species carried by a common . A successful vaccine would not necessarily have to kill the mosquito immediately after it feeds on humans to be effective. Vaccine-induced effects on mosquito survival, blood meal digestion, feeding frequency, reproduction, or physiological processes may have profound effects on the sporogonic development of the parasites and, ultimately, vector transmission potential.

RESEARCH FOCUS: Development of candidate anti-mosquito vaccines that produce host antibodies with an immunopathological impact on the or that disrupt parasite development in the vector.

Genetic Modification of the Mosquito Vector

RESEARCH FOCUS: Further development of molecular-level approaches for understanding the genetics of populations and their natural abilities to transmit malaria parasites.

Drug Development

RESEARCH FOCUS: New or existing drugs that kill or reduce the infectivity of gametocytes or reduce the transmission potential of vectors through disrupting normal sporogonic development.

RESEARCH FOCUS: Vector-based field evaluation of transmission-blocking drugs in areas.

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From 30 Million Cases To Zero: China Creates A Malaria

Over the course of 7 decades, China, the worlds most populous country, succeeded in driving down its malaria burden from 30 million cases per year in the 1940s to zero in 2017 a notable achievement that has been maintained to this day.; On 2 July 2021, representatives from Chinas National Health Commission joined frontline health workers from other countries, WHO experts and global partners in a virtual forum to share reflections and perspectives on Chinas malaria elimination journey.

How Malaria Is Spread

What is a Biological Vector – More Grades 5-8 Science on Harmony Square

The plasmodium parasite is spread by female Anopheles mosquitoes, which are known as “night-biting” mosquitoes because they most commonly bite between dusk and dawn.

If a mosquito bites a person already infected with malaria,;it;can also become infected and spread the parasite on to other people. However, malaria can’t be spread directly from person to person.

Once you’re bitten, the parasite enters the bloodstream and travels to the liver. The infection develops in the liver before re-entering the bloodstream and invading the red blood cells.

The parasites grow and multiply in the red blood cells. At regular intervals, the infected blood cells burst, releasing more parasites into the blood. Infected blood cells usually burst every 48-72 hours. Each time they burst, you’ll have a bout of fever, chills and sweating.

Malaria can also be spread through blood transfusions and the sharing of needles, but this is very rare.

Page last reviewed: 22 August 2018 Next review due: 22 August 2021

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Lao People Democratic Republic

2.2.1. Overview

Lao PDR is a land-locked country, which borders five countries, China, Vietnam, Cambodia, Thailand and Myanmar, respectively. Most of the western border of Laos is demarcated by the Mekong River, which is an important artery for transportation and commerce. Two-thirds of Laos is covered by primary and secondary forests with a mountainous landscape and an abundance of rivers and natural resources which remain intact. The country has a tropical climate with high humidity throughout the year. The Mekong has not been an obstacle but a facilitator for communication between Laos and northeast Thai society reflecting the close contact that has existed along the river for centuries.

Figure 2.

Annual Parasite Incidence , Annual Case Incidence and malaria deaths in Laos from 1987 to 2011. Source: Meeting on Outdoor Malaria Transmission in the Mekong Countries for 13 countries during 12-13 March 2012, Bangkok, Thailand.

2.2.2. Malaria vectors and biodiversity of Anopheles in Laos

2.2.3. Distribution of malaria vectors and behavior of Anopheles in Laos

2.2.4. Implications of changing social and environment conditions on vector and transmission

Vector Species Prevalence In India

Six Anopheles species, Anopheles baimaii, Anopheles culicifacies, Anopheles fluviatilis, Anopheles minimus, Anopheles stephensi, and Anopheles sundaicus are implicated as primary vectors transmitting malaria in different eco-geographical regions of India. In addition, the secondary/local vectors Anopheles annularis, Anopheles nivipes, Anopheles philippinensis, and Anopheles varuna transmit malaria along with either one or two major vectors in different parts of the country. Anopheline vector fauna of this country is further enriched by the recognition of certain of these vector species as species complexes . The anopheline species that have been found as complexes and the members in each of these complexes found in India are: Culicifacies Complex , Dirus Complex , Fluviatilis Complex , Minimus Complex , Sundaicus Complex , Annularis Complex and Subpictus Complex ;. These species, owing to their distinct biological characters and ecological preferences, show a specific distribution pattern. Malaria epidemiology in India is complex and the endemicity varies distinctly in diverse ecosystems of the country. The ecosystems vary in the proportions of two predominant malaria parasites P. falciparum and P. vivax, and the prevalence of the six major Anopheles vector species and their sibling species along with one or two vectors of local importance.

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How Is Vector Used In Real Life

Vectors have many real-life applications, including situations involving force or velocity. For example, consider the forces acting on a boat crossing a river. The boats motor generates a force in one direction, and the current of the river generates a force in another direction. Both forces are vectors.

What Is An Agent Factor

Malaria Transmission And Life Cycle Stock Vector

A factor is a type of agent who sells goods owned by another, called a principal. The factor engages more frequently in the sale of merchandise than the purchase of goods. A factor is distinguished from a mere agent in that a factor must have possession of the principals property, while an agent need not.

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