Mosquitos are widely known throughout the universe and mosquito utilizing several H2O organic structures for engendering ( WHO, 1982 ) . Larval species can be found in about every type of non-flowing aquatic home ground from the boggy borders of big lakes, provided that fish or polliwogs are non present through swamps and fens of all types and sizes along subdivisions of rivers, watercourses, or ditches where the H2O is non fluxing to little aggregations of H2O in stone crannies, tree or stump holes, foliages of pitcher-plants and unreal containers ( Wood, Dang and Ellis, 1979 ) . The climatic and environmental factors are influenced straight and indirectly to the distribution of mosquitoes ( Mafiana et al. , 1998 ) .

Mosquitoes prefer an environment with certain resources which are nutrient, shelter, favorable temperature, rainfall, engendering site and suited humidness in sufficient sum and at the appropriate clip for endurance and development for the eggs of female mosquito to hatch ( Romoser & A ; Stoffolano, 1998 ) . The genteelness of assorted mosquito species is late increase contributed of the recent addition in ecological and environmental alteration due to agricultural activities and urbanisation ( Amusan et al. , 2005 ) .

Temperature and the handiness of appropriate aquatic genteelness home grounds are the two environmental variables that most impact the copiousness of mosquitoes. Temperature impacts both the survivorship and developmental rate of mosquitoes ; surface wetness, as mentioned above, limitsA the population size of sub-adult mosquitoes. These two parametric quantities, temperature and surface wetness, will be used to coerce the theoretical account mosquito population ( Kettle, 1995 ) . Changeless surveies on biological science and larval ecology of mosquitoes have been observed as of import tools in mosquito control. Such surveies will assist to find the bing and vanishing mosquito species and the extent of their distribution ( Mafiana et al. , 1998 & A ; Anyanwu et al. , 1999 ) . Mosquito can do more human agony than any other beings. Mosquito bite cause terrible tegument annoyance through an allergic reaction to the mosquito ‘s spit which can do human tegument ruddy bump and itchiness. Mosquito besides carry disease that afflict human such as malaria, xanthous febrility, phrenitis and dandy fever virus which a mosquito bites infected the host, the virus will be transferred into it, and the transmittal concatenation starts once more ( WHO, 1997 ) .

The life rhythm of the mosquito is begins with the female mosquito will put eggs at any surface H2O, which hatches as a larvae in the right conditions. The larvae so develop into several instar phases before come ining pupation. After the pupation, the mosquito emerges as an grownup which is besides called as amigo. Adults by and large mate within the first few hours of outgrowth, and so the grownups will rests on the surface H2O for a short clip to let itself to dry and all its organic structure parts to indurate. Blood eating does non happen for a twosome of yearss after the grownups emerge including the coupling. Once to the full developed, the female mosquito will continue to happen a protein beginning for their eggs which is blood. After seize with teething, the female remainders while take attention of their eggs and repetition thegonotrophic rhythm once more.

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1.2 Aims

The aims of this survey are:

To cognize the relationship between mosquito genteelness and environment.

To cognize the effects of environmental factors on mosquito copiousness.

To analyze the life rhythm of mosquito.

To analyze the consequence of mosquito to human wellness.

1.3 Significances of survey

Environment plays an of import function on life rhythm of mosquito. So, in this survey and research, it can demo us the interactions between environment and life rhythm of mosquito. In this research survey, I would wish to cognize the effects of environmental factors such as pH, rainfall and temperature of the site on mosquito copiousness by utilizing the larvae one. Mosquito copiousness is really relate with the sum of rainfall and contribute to increase the figure of larval genteelness sites, the spacial relationship between larval home ground handiness and grownup mosquito copiousness is non clear.

In these survey besides, I would cognize the disease that mosquito can convey which consequence the human wellness. We can cognize that mosquitoes are a vector agent that carries disease causation viruses and parasites from individual to individual without catching the disease themselves. Furthermore, I will cognize the methods used for mosquito control that can cut down the disease that mosquito can convey to human. Depending on the state of affairs, beginning decrease, biocontrol, insecticides to kill larvae and to be specific, the grownups may be used to pull off mosquito populations.

In these research survey besides, we would wish to cognize when the suited genteelness clip for mosquito is really. It is said that many species disappear about wholly during the dry season and it will be most productive towards the terminal or merely after the moisture season, when most species will hold built up to a extremum and the bounds of the genteelness sites have temporarily stabilized.

1.4 Problem Statement

Mosquito had been known for a century which is they carry diseases which can do human to decease. These can be described as the mosquito can do more human agony than any other being. Furthermore, mosquito bite can do terrible tegument annoyance through an allergic reaction to the mosquito ‘s spit which can do homo ‘s tegument itchiness and ruddy bump. Mosquito carry several diseases which are malaria, filarial diseases ( dog bosom worm ) , virus dandy fever, phrenitis and xanthous febrility. These diseases can endure human being and can do human being to decease.

Presents, mosquito distribution is increasing in Malaysia because of certain conditions that contribute to mosquito genteelness. More than that, population in Malaysia besides increases by twelvemonth to twelvemonth. So, this besides will increase the figure of instances that inflict the human by mosquito.

Chapter 2


2.1 Environment

In general, environment is really referred to the surrounding of something or an object. The natural environment is contrast with the built environment which includes the countries and constituents that are strongly influenced by the homo. An ecosystem is a sort of natural which include all of workss, animate beings and micro-organisms in an country working together with all of the inanimate physical factors of the environment.

There have been several surveies that have focused on how environmental factors affect the mosquitoes breed ( Yee 2008 ) . The environmental factors and climatic are influenced the distribution of mosquitoes which in straight or non ( Mafiana et al. , 1998 ) . Mosquitoes prefer an environment with certain status that help their genteelness which in appropriate sum and clip for endurance and development ( Romoser & A ; Stoffolano, 1998 ) .

The efficaciousness of any mosquito larvae may nevertheless, depend upon its bioavailability for mark larvae in the environmental H2O together with the ain tolerance degree of each larval. Several environmental parametric quantities may act upon the public presentations of a given larvae ( Bourguet et al. , 1996 ) .

2.2 Biodiversity

Harmonizing to Convention on Biological Diversity ( CBD ) stated that ‘biodiversity ‘ agencies that the variableness among populating beings from all beginnings including, inter alia, tellurian, marine and other aquatic ecosystems and the ecological composites of which they are portion which includes diverseness within species between species and of ecosystems.

In the last decennary, biodiversity concerns have been in the head of preservation attempts worldwide ( Environment Canada, 1994 and UNEP 1995 ) . Biodiversity has been defined in assorted ways ( McNeely et al. , and Salwasser, 1990 ) but the term has by and large been used in a really comprehensive mode intending the variableness of life which are composing, construction and map.

Biodiversity can be represented as an interlocked hierarchy of elements on several degrees of biological organisation ( Noss, 1992 ) . Since the term ‘biodiversity ‘ transcends all degrees of life from cistrons to communities and all spacial and temporal graduated tables ( Noss, 1990 and Savard, 1994 ) , it has generated a batch of confusion and misinterpretation ( West, 1993 and Lautenschlager, 1997 ) . However, when understood and used decently, biodiversity constructs can supply a utile model for preservation attempts ( Savard, 1994 ) .

Harmonizing to Mittermeier et al. , ( 1999 ) and Myers et al. , ( 2000 ) biological rich countries are found in a high scope across the altitudinal fluctuation associated with diverse home grounds. Further, as per their positions, most of the hot musca volitanss and countries of high biological diverseness are concentrated in hilly and cragged scopes where there are diverse home grounds. There are evidenced which the rich mosquito zoology diverseness, but there is about no record about species profusion and its composing in diverse home grounds ( Mahesh and Jauhari, 2000 ) .

2.3 Mosquito

Mosquitos are insects belonging to the order Diptera, the True Flies. Like all True Flies, they have two wings, but unlike other flies, mosquito wings have graduated tables. Female mosquitoes ‘ mouthparts form a long piercing-sucking proboscis. Males differ from females by holding feathery aerial and mouthparts non suited for piercing tegument. A mosquito ‘s chief nutrient is nectar or similar sugar beginning. There are over 2500 different species of mosquitoes throughout the universe ; about 200 species occur in the United States with 77 species happening in Florida ( Darsie et al. , 2002 ) .

2.3.1 Life Cycle of Mosquito

The mosquito is really been through four separate and distinguishable phases of its life rhythm which are egg, larva, pupa and grownup. Eggs are laid one at a clip or attached together to organize “ tonss ” . They float on the surface of the H2O. Most eggs hatch into larvae within 48 hours, others might defy subzero winters before hatching. Water is a necessary portion of their home ground.

The larva lives in the H2O and comes to the surface to take a breath. Larvae shed their teguments four times, turning larger after each shed. The larvae provender on micro-organisms and organic affair in the H2O. During the 4th molt the larva changes into a pupa.

The pupa phase is a resting clip which is non-feeding phase of development but pupa are nomadic, reacting to the light alterations and traveling with a somersault of their dress suits towards the underside or protective countries. This is the clip the mosquito changes into an grownup. When development is complete, the pupa tegument splits and the grownup mosquito ( imago ) emerges.

The freshly emerged grownup remainders on the surface of the H2O for a short clip to let itself to dry and all its organic structure parts to indurate. The wings have to distribute out and dry decently before it can wing. Blood eating and coupling does non happen for a twosome of yearss after the grownups emerge.

2.3.2 The Vector

Mosquitos are known vectors of several disease doing pathogens which affect many 1000000s of people all over the universe. Aedes aegypti is known to transport dandy fever, xanthous febrility and chikungunya while malaria is carried by Anopheles stephensi and filarial disease by Culex quinquefasciatus ( WHO, 1992 ) . Mosquito transmitted diseases continue to be a moajor beginning of unwellness and decease. Most parasitic diseases are tropical and ontensifying globalisation and climatic alteration are increasing the hazard of undertaking arthropod borne unwellnesss ( Guenier et al. , 2004 ) .

Repellents play an of import function in protecting worlds from the bites of insect plagues. An effectual and safe repellant will be utile in cut downing human and vector contact and thereby aid in the decrease of vector borne disease transmittal ( Kalyanasundaran & A ; Mathew, 2006 ) . Meanwhile, harmonizing to Gupta & A ; Rutledge ( 1994 ) , the usage of personal protection steps such as the application of repellants of open tegument has long been advocated to minimise human contact with vector and nuisance mosquitoes.

Chemical repellants are of import in protecting people from blood eating insects, ticks, touchs and other arthropods and may therefore besides cut down transmittal of arthropod borne diseases ( Brown & A ; Hebert, 1997 ) . Peoples populating in the distant rural countries and the poorer subdivision of society infinitely suffer from many vector borne diseases, peculiarly malaria, due to miss of simple and inexpensive methods of personal protection ( Karunamoorthi et al. , 2008 ) .

2.3.3 Transmission

Virus transmittal of mosquito will impact the homo after being bitten and human is the reservoir of the virus. In mosquito, the virus will take for approximately 8 to 10 yearss to develop. A female mosquito may convey the virus to its offspring through transovarian transmittal, but it is non frequent. These virus or disease from mosquito will convey into human circulation during the blood repast clip. The virus will develop in the human circulation which the human incubation period takes about 3 to 14 yearss. If a mosquito bites, the virus will so convey into the host and the transmittal concatenation starts once more ( WHO, 1997 ) . Vertical transmittal of dandy fever virus is really rare. Nonetheless, 2 instances were reported in Malaysia in 1996 ( Chye et al. , 1997 ) .

2.3.4 Factor Contribute to the Disease Outbreak

The happening of mosquito disease is depends of several factors, including the denseness of mosquito vectors. For illustration the dandy fever virus which is carried by the Aedes aegypti that is needed to prolong dengue virus transmittal epidemically or endemically has yet to be determined. Virus transmittal increased by denser human population. Urbanization in tropical states has resulted in both a proliferation of Aedes aegypti and an addition in the figure of susceptible human hosts ( WHO, 1997 ) .

Harmonizing to McMichael and Woodruff ( 2008 ) , mosquito borne infections tend to increase with warming and certain alterations in rainfall form. Higher rainfall will rise the disease transmittal. Therefore, clime alteration will impact the possible, seasonal transmittal and geographic scope of assorted vector borne diseases. These diseases would include all H2O borne diseases, such as malaria, dandy fever febrility and xanthous febrility ( Haines et al. , 2006 ) .

Climate alteration will impact the biodiversity and the ecosystem goods and services that we rely to human wellness. Changes in temperature and rainfall consequence the distribution of the diseases vectors, such as Aedes mosquitoes ( Haines et al. , 2006 ) . Recent reappraisals suggest that dandy fever ‘s scope and incidence may be altering as a consequence of clime alteration ( Gubler, 2002 ) .

Most of the transmittals of mosquito borne diseases are sensitive to endure conditions for several grounds here, mosquito need standing H2O to engender, and a warmer temperature is critical to adult feeding behaviour, the rate of larval development and velocity of replicate of virus ( Hales and Panhius, 2001 ) .

Haines et al. , ( 2006 ) stated that alterations in clime that can impact the transmittal of vector borne infective disease include temperature, rainfall alterations, humidness, dirt wet and sea degree rise and it will do the fluctuation of the overall incidence of the disease, where less, the geographical distribution of disease besides alteration.

2.3.5 Breeding and Larval Habitat

Harmonizing to Queensland Government ( 2005 ) , the mosquito is frequents backyards in hunt of containers keeping H2O inside or outside the place. For illustration tins, pails, jars, pot workss dishes, vases, birdbaths, boats, discarded with no rims tyres, roof troughs blocked by foliages, containers, tarpaulins and black plastic. It besides can engender in natural containers like fallen thenar fronds. Besides that, even in a drier status it besides breeds in H2O in subterraneous sites such as Wellss, telecommunication cavities, sump cavities and gully traps.

Furthermore, harmonizing to Queensland Government ( 2005 ) besides stated that clime of tropical and semitropical parts are really suited for mosquito genteelness. This is because of high temperature and high visual aspect of quiescent H2O organic structure. With this, it makes the clime in Malaysia is tropical and the temperature are within 20A°C to 30A°C throughout the twelvemonth and with high norm rainfall which is about 2500mm in the Peninsular Malaysia and it is become the most suited genteelness conditions and home ground for mosquito.

Harmonizing to White ( 2004 ) , mosquitoes breed in H2O, on occasion lodging eggs straight on H2O, but by and large utilizing a assortment of moist surfaces, tree holes, and containers and the development clip for larvae depends on specific environmental conditions such as temperature, alimentary supply, grade of available visible radiation, with most tropical mosquito larvae developing in about 1 hebdomad, while the larvae of many species endemic to temperate zones may overwinter.

Human activities, such as the production of a big sum of environmental dust that holds H2O pools including disposable bottles, tins, discarded tyres and storage of H2O on or around life premises when dependable piped place H2O supplies are unavailable or undependable, may markedly increase available mosquito engendering sites and have been peculiarly implicated, as mentioned above, in the pronounced airing of Ae. aegypti ( along with the dandy fever instances it really expeditiously vectors ) throughout most of the tropical universe including countries from which both had been eradicated ( Gubler, 1989 ) .

2.3.6 Dengue Diseases

Dengue diseases are included dandy fever febrility ( DF ) , dengue haemorrhagic febrility ( DHF ) and dengue daze syndrome ( DSS ) are serious mosquito-borne diseases. These diseases are normally found in Southeast Asiatic states including Malaysia ( Lee, 2000 ) .

The geographical spread of both the mosquito vectors and the viruses has led to the planetary revival of epidemic dandy fever febrility and outgrowth of dandy fever hemorrhagic febrility ( dengue/DHF ) in the past 25 old ages with the development of hyper endemicity in many urban centres of the Torrid Zones ( WHO, 2009 ) .

Harmonizing to World Health Organization ( WHO, 2009 ) studies, an estimated 50 – 100 million dandy fever infections occur worldwide every twelvemonth, including up to 500,000 instances of DHF. Forty per cent of the universe ‘s population resides in countries where transmittal occurs.

Dengue febrility patient have symptoms of achings in the musculuss and articulations, concerns and febrility which last for two or three yearss. The stage of the unwellness is replaced by a period of one to three yearss continuance when there is a return to both normal organic structure temperature and good wellness. But the febrility shortly returns, together with strivings and roseola which covers most of the organic structure apart from the face. Although dandy fever is class by infirmity it is seldom fatal ( Snow, 1974 ) .

2.3.7 Control of Mosquito Diseases

Presents, mosquito diseases have been good known around the worldwide. They carry diseases which can do human to decease and suffer for their life. For illustrations malaria, filarial diseases, viruses dengue, phrenitis and xanthous febrility. These diseases have cause 1000000s of infections occur worldwide every twelvemonth. So, we should forestall or command the mosquito diseases from distributing around the universe.

An effectual manner to forestall all of these diseases is to command the growing of mosquito population. A recent alternate manner that originated from progresss in familial research is the possibility to bring forth transgenic mosquitoes. Although this alternate is already a success for the instance of malaria mosquitoes. Now, it has been suggested and there are some research initiatives in this way, which genetically modified mosquitoes introduced in the environment, can kill off malaria one time and for all ( Catteruccia et al. , 2003 ) .

The 2nd alternate manner for mosquito control is by adulticide crop-dusting, it is far more controversial, and its effectivity is limited. Some of wellness section functionaries and Mosquito Abatement Districts ( MAD ) employees pointed out that surveies have shown merely a 30 % decrease in mosquito population after spraying. Surveies like these are controversial because as community of the environment, this experiment is really making in a controlled environment that exaggerates spraying effectivity, so percentages in the field are less. Nevertheless, grounds suggests that combined usage of both larvicides and adulticides to cut down Numberss of mosquitoes will diminish the figure of West Nile Virus ( WNV ) infections in worlds ( Bowman et al. , 2005 ) .

Many territories have reduced their usage of adulticide crop-dusting because of concerns about wellness and environmental impacts. However, adulticide crop-dusting may be justified during a disease eruption ( Peterson et al. , 2006 ) .

There are attack to diminish or minimise the incidence of these diseases to distribute and to command mosquito vectors chiefly by application of insect powders to larval home grounds, destructing unwanted containers and educating the populace ( Corbel, 2004 ) . During epidemics, these steps are complemented by insecticide space-spraying against grownup mosquitoes. However, aerial poisons for eliminating A. aegypti are non effectual, since this species is extremely domesticated and many grownups rest in concealed topographic points indoors ( Ciccia, 2000 ) . Attacking the engendering site of mosquito with larvicides is a possible and effectual manner to decrease mosquito population for a higher per centum than other ways.

2.4 Factor Effect Mosquito Breeding

Mosquitoes prefer an environment with certain resources which are nutrient, shelter, favorable temperature, rainfall, engendering site and suited humidness in sufficient sum and at the appropriate clip for endurance and development for the eggs of female mosquito to hatch ( Romoser & A ; Stoffolano, 1998 ) . The genteelness of assorted mosquito species is late increase contributed of the recent addition in ecological and environmental alteration due to agricultural activities and urbanisation ( Amusan et al. , 2005 ) .

Wu et Al. ( 2007 ) indicated that the conditions variableness such as monthly upper limit, minimal temperature, rainfall and comparative humidness identified as a meaningful and important indexs for the increasing happening of dandy fever febrility in Taiwan part. It is besides widely accepted that the distribution and kineticss of vector borne diseases infections are peculiarly sensitive to meteoric conditions, by virtuousness of the sensitiveness of many species of mosquitoes to fluctuations in temperature, comparative humidness, rainfall, vaporization and measures of standing H2O quality used as engendering sites ( Johansson et al. , 2009 ) . Specifically, the epidemic behaviour of dandy fever viruses apparently relates closely with fluctuations in temperature and rainfall ( Halstead, 2008 ) .

2.4.1 Rain

Precipitation is one of the most of import elements for the genteelness and development of mosquitoes ( Kelly-Hope et al. , 2004 ) . All mosquitoes have aquatic larval and pupa phases and hence require H2O for engendering ( Clements, 1992 ) . Considerable grounds has occurred to demo that heavy rainfall and implosion therapy can take to increased mosquito genteelness and eruption of diseases. For illustration, high rainfall has been associated with eruptions since 1928, and 46 to 50 eruption location received higher than mean rainfall in the predating month ( Kelly-Hope et al. , 2004 ) .

The association of dandy fever epidemics with rainfall could be explained by additions in grownup endurance and feeding activity of the vector mosquito. However, some researches gave beliing grounds on the relationship of meteoric factors to dengue incidence ( Kanchanapairoj et al. , 2000 ) .

Harmonizing to Mafiana et al. , ( 1998 ) , tree holes can merely retain H2O for a short clip period and dry up at the clip there is no rain. This is the ground to explicate the low part of tree holes to the genteelness of mosquitoes.

2.4.2 Temperature

Warm temperature can increase or cut down survival rate, depending on the vector, its behaviour, ecology and many other factors. A 2A°C addition in temperature would at the same time lengthen the lifetime of the mosquito and shorten the extrinsic incubation period of dandy fever virus, ensuing in more septic mosquitoes for a longer period of clip ( Focks and Barrera, 2007 ) .

Temperature and the handiness of appropriate genteelness home grounds are the two environmental variables that most impact the copiousness of mosquitoes ( Kettle, 1995 ) . Temperature is really can do both the survivorship and development rate of mosquitoes.


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