The Asian Tiger Mosquito Dengue - Essay Example

THE ASIAN TIGER MOSQUITO DENGUE INTRODUCTION There a quite a lot of mixed feelings from people with regards to the topic area about insects. Regardless of their size, the impacts of the insects can be far reaching and often devastating than generally imagined by the ordinary person. According to a study conducted by Miller and Harvey (2007), there are approximately about 750,000 known species of insects that can be described. However, the list can even exceed three million including unknown species of existing insects. The study also asserts that about 0.5 % of the known insects have negatively affected human life directly. Mosquitoes in general are widely known insects which are parasitic and transmit diseases among the human beings. Against this background, this essay seeks to critically review the diseases caused by mosquitoes particularly the denegue fever. THE ASIAN TIGER MOSQUITO IntroduceSpecieWHSAPBio (N.D) provides the following specific details about the nature and structure of the Asian Tiger Mosquito. Scientific Name: Aedes albopictus Classification: Kingdom animalia, Phylum anthropoda, Class insect, Order diptera, Family culicidae, Genus aedes Associated Species: Aedes, Culex, Toxorhynchites, Trichoprosopon, Uranotoenia and Armigeres. Description The Asian Tiger Mosquitoes are distinctly shiny and they have black scales which have a silver white band down the middle of their back. This is regarded as a medium sized mosquito with about 2 to 3 millimeters in length. It appears as if it is wearing stripped black and white socks on its legs. According to Novak (1992), this type of mosquito is very aggressive during the daytime particularly early in the morning as well late afternoon. Between 10 in the morning and 3 in the afternoon, this mosquito is believed to be on its peak period of biting. Origin and Distribution: As implied by the name, this type of mosquito originates from the continent of Asiain various areas such as New Guinea, India, Pakistan, Madagascar, China, Korea and Japan. Other recent studies have also indicated that this kind of mosquito specie is also found in the islands of Hawaii and South Pacific. There have also been studies which indicate that this specie also exists in the states of Delaware, Texas, New Jersey and Maryland. Habitat: The Asian Tiger Mosquitoes are commonly known to favour breeding in natural as well as artificial containers with stagnant water such as tree holes, tires, empty tins, flower pots, bottles and a lot of other disused household cans lying idle and trapping water. Life cycle: According to information obtained from IntroduceSpeciesWHSAPBio (N.D), the egg is the starting point in the life cycle of the Asian Tiger Mosquitoes. It can hatch between a period which is as early as four days to one year depending on the immersion of the eggs. Following the hatching of the eggs, most of the larvae live underwater and they feed on anything that is smaller than 10 microns that is found in the water. It takes 3 days to several weeks for a larva to fully develop and become pupae. After about two or three days of inactivity on the waters surface the pupae transforms into an adult mosquito. The life span of an adult mosquito is usually between one to two months depending on their food sources and climate conditions. Source of Food: The Asian Tiger Mosquito is a parasite which feeds on blood from man, animals and birds (Novak 1992). CAUSES OF DENGUE FEVER There are a variety of causes that contribute to the development of dengue fever. According to a study by Tenenbaum (2002), the following causal factors contributed to the increase of mosquito related diseases. 1. Unprecedented increases in population particularly in the developing tropical countries led to unsanitary living conditions. The use of unsafe water systems as well as, inefficient sewage and waste systems contributed to the problem since this brought the mosquitoes to live closer to people. 2. The used of plastic containers which are not properly disposed or biograded has also contributed to the increasing number of mosquitoes since the breeding areas would have increased. 3. The manufacture of tire for automobiles has significantly increased and the wanton disposal of these tires has also contributed to the increase of breeding grounds for mosquitoes. 4. It can be noted that the methods of control that were used since the 1970s were becoming ineffective in combating the growth of mosquitoes which made it difficult to control the spread of dengue fever. “These factors have been collectively responsible for the global emergence of epidemic dengue/DHF [dengue hemorrhagic fever, the bleeding form of disease] in the past 15 years," (Tenenbaum, 2002). THE DENGUE FEVER Definition Dengue is a disease caused by mosquito bites and can be transmitted. According to Shepherd, et.al. (2007), “dengue is caused by infection with 1 of the 4 serotypes of dengue virus (such as DENV-1, DENV-2, DENV-3, DENV-4).” The detailed discourse about these viruses (N.D) states that, “Dengue viruses are small, spherical, single-stranded enveloped RNA viruses of the family Flaviviridae, genus Flavivirus. Infection with one dengue serotype confers lifelong homotypic immunity and a very brief period of partial heterotypic immunity, but each individual can eventually be infected by all 4 serotypes. Several serotypes can be in circulation during an epidemic.” Types of Dengue Basically, there are mainly three identified types of dengue fever: (a) the classic dengue fever is characterised by symptoms such as skin rashes, general weaknesses of the body, severe headaches as well as fever. According to Dorothy (N.D.), “this form is not fatal and rarely affects children”. Shepherd, et.al. (2007) also concurs that “initial dengue infection may be asymptomatic, may result in a nonspecific febrile illness, or may produce the symptom complex of classic dengue fever (DF).” It has also been noted that there is a mild dengue fever which exhibits symptoms that are just similar to those of classic dengue fever but only last for three days. (b) The dengue hemorrhagic fever (DHF) is characterised by symptoms such as vomiting, severe abdominal pains and coughing. The DHF affects children below 15 years old unlike the classic dengue fever. Shepherd, et.al. (2007) observed that with this type of syndrome, “A small percentage of persons who have previously been infected by one dengue serotype often develop bleeding and endothelial leak upon infection with another dengue serotype.” (c) Finally, there is the dengue shock syndrome (DSS). This has symptoms which have the same characteristics with DHF. In her study on Dengue, Dorothy (N.D.) pointed that, “this disease mainly causes abnormal blood clotting that can result in internal bleeding and organ failure, not to mention circulatory collapse.” This type of dengue may cause death to the infected person if it is not diagnosed and treated immediately. Pathophysiology Shepherd, et.al.(2007) who immensely contributed to research on the dengue fever, suggested on the following on its Pathophysiology: Dengue infection is caused by 1 of 4 related, but antigenetically distinct, viral serotypes: dengue is caused by infection with 1 of the 4 serotypes of dengue virus (such as DENV-1, DENV-2, DENV-3, DENV-4). Infection with one dengue serotype confers lifelong homotypic immunity and a very brief period of partial heterotypic immunity, but each individual can eventually be infected by all 4 serotypes.” The dengue virus has been found to have an incubation period of about 14 days from bites of an Asian Tiger Mosquito. After the incubation has taken place after the bites, acute febrile illness often occurs after a period ranging from about five to seven days (Shepherd, et.al. 2007) Prevalence of Dengue in US The known earliest documented migration of the Asian Tiger Mosquitoes was in 1985 in Houston, Texas where it was noted that the international transportation of used tires prompted the migration of mosquitoes from Asia. “The Asian Tiger Mosquito is currently located in over 678 counties and 25 states. It is a major problem especially in the southeastern states of the US. The states with the worst Asian Tiger Mosquito problems include the following: Florida, North Carolina, South Carolina, Georgia, Tennessee, Texas, and Louisiana. Although it does not seem to be spreading westward and northward, the Asian tiger mosquito has spread as far north as Pennsylvania” (IntroduceSpeciesWHSAPBio, (N.D). Shepherd et.al. (2007) also observed that there were a total of 90 confirmed cases of dengue fever that were imported into the United States and one fatality was reported in 1998. It is estimated that the average cases of dengue fever are about 100 per year but the figures are thought to be higher since reporting is voluntary and the US physicians are not yet aware of the manifestations of the symptoms. By these figures, it is eminent, that this illness should alarm residents in the mentioned area of infestations due to the serious repercussions indicated in this disease. Mortality/Morbidity According to Shepherd et.al. (2007), the severity and intensity of this illness on people depends on different factors such as: age, ethnic background, kind of nutrition, as well as the sequence of infection with different dengue serotypes. It can be noted that early diagnosis of the symptoms and quality of care given to the patient largely affect the speed of recovery from the infection. According to the same study, the mortality rate associated with dengue fever is less than 1% while the fatality rate in patients who meet criteria for dengue hemorrhagic fever is approximately 6%. Sex Both sexes, male and female are susceptible to the impacts of this disease. Age The dengue fever can affect all the age groups of people though there are some types that do not affect a certain age group such as DHF and DSS that affect children below 15 years of age. However, there are documented cases where the entire family is affected by dengue fever as a result of the feeding habits of the Asian Tiger Mosquito. An infected mosquito can feed on the blood of all family members in a house and it will infect each family member. Thus cases of entire families to develop infection within a 24- to 36-hour period as a result of the bites from a single infected mosquito are not unusual (Shepherd et.al. 2007). Clinical Symptoms A person who has been infected with dengue fever often displays the following symptoms: fever, headache, vomiting and nausea, skin rashes. If they are not immediately diagnosed, the patients show the following symptoms: abdominal pain, restlessness, bleeding from the nose or gums, fatigue, sore throat and cough. In some instances, dehydration is also associated with this kind of illness. According to Shepherd et.al. (2007), a tourniquet test is performed “by inflating a blood pressure cuff on the upper arm to midway between diastolic and systolic blood pressures for 5 minutes. The results are considered positive if more than 20 petechiae per square inch are observed on the skin of the arm.” Causes Dengue infection is caused by 1 of the 4 dengue viruses (ie, DENV-1, DENV-2, DENV-3, DENV-4) and is transmitted to humans through bites inflicted on a person by an infected mosquito (Shepherd et.al. 2007). Treatment Various forms of treatment of this disease are available in the event the symptoms have been diagnosed. It is recommended that a physician should be consulted if any person displays the above mentioned symptoms. Combined medical care and drugs are also used to relieve a person or for quick recovery of dengue fever. Tourniquet test is the first step used to diagnose this illness as well as to determine if the person is positively affected with the virus. Any decrease in platelet count should be immediately addressed. Where there might be an incidence of dehydration related to this illness, there is need for intravenous fluid administration. Hospitalization is recommended for cases like these. Shepherd, et.al. (2007) posit to the effect that patients with dengue hemorrhagic fever or dengue shock syndrome may only be discharged from the hospital when they meet the following conditions: Afebrile for 24 hours without antipyretics Positive recovery and signs of good appetite Adequate urine levels Stability in hematocrit level Discharged after 48 hours from recovery from the shock No sign respiratory distress Platelet count greater than 50,000 cells/μL” Medications There is no specific antiviral medication that is currently available for the treatment of dengue infections as shown by medical studies. It is important not to give non steroidal anti inflammatory drugs (NSAIDs) for symptoms like fever. Paracetamol can be administered to treat fever and pain. The best remedy for severe symptoms is to hospitalize the infected person immediately. Prevention The best remedy for the treatment of dengue fever is avoiding being bitten by the Asian Tiger Mosquito since there is no specific cure for this ailment once infected. Medical professionals advise people to prevent mosquito bites by following the listed measures according to (Shepherd et.al. 2007). If possible, avoid visiting areas where it is prevalent. Wear N,N-diethyl-3-methylbenzamide (DEET)–containing mosquito repellant. Wear protective clothing laced with permethrin insecticide. Remain in well-screened or air-conditioned places. May use mosquito nets. Eliminate the mosquito vector using indoor sprays. Destroy probable habitats of mosquitoes such as tires, old tins and pots which keep stagnant water. CONCLUSION The Asian Tiger Mosquito has impacted on a number of lives as a result of the infectious virus it carries. However, a question that begs an answer is: Are mosquitoes beneficial to humankind? Probably to a little extent in that they are part of the ecosystem otherwise they are a menace to humankind. People should be preoccupied with knowing the types of the insects, their impacts to life with regards to the spread of diseases, conduct more research on medication of diseases caused by these insects as well as measures that can be put to prevent the spread of these diseases. Cleanliness of the environment is a virtue and efforts should be made to destroy all the places that are breeding grounds for the mosquitoes. This is the only viable option that cab be implemented with regards to eradication of the diseases related to mosquitoes. References Crans, W.J. The Asian Tiger Mosquito in New Jersey. Rutgers Cooperative Extension Fact Sheet # FS845. Dorothy, J. Dengue (Break-Bone Fever). Retrieved on April 19, 2010 from IntroduceSpeciesWHSAPBio. The Asian Tiger Mosquito. Retrieved on April 19, 2010 from Miller, S. & Harley, J. (2007). Zoology. McGraw Hill Companies, Inc. Novak, R. (1992). The asian tiger mosquito, Aedes albopictus. Wing Beats, Vol. 3(3):5. Shepherd, S.M., Hinfrey, P.B. & Shoff, W.H. (2007) Dengue Fever. eMedicine: Infectious Diseases from webMB. Retrieved on April 19, 2010 from Read More