Diverse Reactions of The Asian Tiger Mosquito - Essay Example

INTRODUCTION Diverse reactions are elicited from people on the subject of insects. The rationale for this could be due to their minute and microscopic structure which contributes to a seemingly silent evolution. However, a study by Miller and Harvey (2007) revealed that there exists approximately 750,000 described insect species which can extend to an estimate of about three million including undescribed species. The study further averred that from the abovementioned figures, only about 0.5% have directly and adversely affected the human life. Mosquitoes, specifically, have been stereotyped as parasites and vectors of diseases. It is in this regard that this essay aims to closely review the diseases inflicted by this specific species, particularly the dengue fever. THE ASIAN TIGER MOSQUITO A close review of the nature and structure of the Asian Tiger Mosquito is accurately provided by IntroduceSpecieWHSAPBio with the following significant details, to wit: 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 and Characteristics. The Asian Tiger Mosquito have a distinct shiny black scales with a silver white bands down the middle of its back. It is about 2 to 3 millimeters in length and considered medium sized for a mosquito. When one sees it, there seems to be black and white striped socks on its legs. Novak (1992) futher describes it as “a very aggressive daytime biter with peaks generally occurring during the early morning and late afternoon”. The identified peak period during which this type of mosquito bites is from 10 in the morning to about 3 in the afternoon. Origin and Geographic Distribution: As the name implies, this species originated from the continent of Asia with diverse areas ranging from New Guinea, India, Pakistan, Madagascar, China, Korea and Japan. (Crans) Recently, studies reveal that this species have been found in the islands of Hawaii and South Pacific. There have been statistics showing that population of these species were identified in the states of Texas, Maryland, Delaware, and New Jersey. Habitat: Asian Tiger Mosquitoes are known to breed in natural and artificial containers with water such as tree holes, bushes, tires, leaf axils, flower pots, bottles, and a variety of discarded household containers left unchecked. Life cycle: Starting out as eggs, the Asian Tiger Mosquitoes “hatch from as early as 4 days to as long as one year depending on the immersion of the eggs. After the eggs hatch the most of the larvae live underwater. They are filter feeders so they feed on anything that is smaller than 10 microns that is already in the water. It takes a larvae 3 days to several weeks to fully develop and become pupae. After two or three days of inactivity on the water's surface the pupae transforms into an adult mosquito”. (IntroduceSpeciesWHSAPBio) An adult mosquito usually lives from one to two months depending on their food sources and climate conditions. Feeding: Novak (1992) noted that the Asian Tiger Mosquito feeds on a variety of hosts which include man, animals and birds. FACTORS THAT LEAD TO DENGUE FEVER There are a variety of factors leading to dengue fever. A study written by Tenenbaum (2002) on Mosquito Bytes reveals the following: 1. An increasing population especially in developing tropical countries resulted in unsanitary living conditions, unsafe water systems, inefficient sewage and waste systems, brought about mosquitoes living closer to people. 2. The changing lifestyles of people caused a utilization of plastic containers which are not disposed of properly nor biodegraded. 3. The increasing numbers of automobiles caused increase in manufacture of tires. Those used tires which are not properly cleaned and discarded became breeding areas of mosquitoes. 4. The increase in commercial travels of people and used tires enabled the transport of disease carrying mosquitoes. 5. The control methods that were used since the 1970s were not effective in eradicating mosquitoes and thereby could not control the proliferation of the dengue fever. As a result, as indicated by Tenenbaum, (2002) “collectively, these factors have been responsible for the global emergence of epidemic dengue/DHF [dengue hemorrhagic fever, the bleeding form of the disease] in the past 15 years," THE DENGUE FEVER Definition Dengue is an insect related disease transmitted to humans from the bite of an infected mosquito. Medically, dengue is “caused by infection with 1 of the 4 serotypes of dengue virus (ie, DENV-1, DENV-2, DENV-3, DENV-4)”. (Shepherd, et.al. 2007) The detailed discourse on these viruses are hereby quoted: “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 There are three (3) identified types or classes of dengue fever: (1) the classic dengue fever exhibit symptoms such as fever, joint ache, severe headaches, weakness, and skin rashes. According to Dorothy, “this form is not fatal and rarely affects children”. In addition, Shepherd, et.al. (2007) revealed 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).” There is a mild dengue fever which exhibit symptoms that are basically the same as the classic dengue fever but last for three days. (2) The dengue hemorrhagic fever (DHF) exhibit symptoms such as coughing, vomiting, and severe abdominal pains. Unlike the classic dengue fever, the DHF affects children below 15 years old. Shepherd, et.al. (2007) averred that in this syndrome “a small percentage of persons who have previously been infected by one dengue serotype develop bleeding and endothelial leak upon infection with another dengue serotype”. (3) Finally, there is the dengue shock syndrome (DSS) exhibits symptoms which are the same as DHF. Dorothy, in her study on Dengue, wrote that “this disease causes abnormal blood clotting that can result in internal bleeding and organ failure, not to mention circulatory collapse.” If not immediately diagnosed and treated, this type of dengue may cause death to the afflicted person. Pathophysiology Shepherd, et.al.(2007) who made an extensive research on the dengue fever, stated the following on its Pathophysiology, to wit: “Dengue infection is caused by 1 of 4 related, but antigenically distinct, viral serotypes: dengue virus 1 (DENV-1), dengue virus 2 (DENV-2), dengue virus 3 (DENV-3), and dengue virus 4 (DENV-4). Each serotype is known to have several different genotypes. 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.” From a bite of an Asian Tiger Mosquito, the dengue virus has been found to have an incubation period of from three to 14 days. Accordingly, after incubation, acute febrile illness occurs from a period of five to seven days. (Shepherd, et.al. 2007) Statistics in the US The earliest documented migration on the Asian Tiger Mosquito was in 1985 at Houston, Texas. These mosquitoes were transported from Asia through the international trade of used tires. According to IntroduceSpeciesWHSAPBio, “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. States with the worst Asian Tiger Mosquito problems are 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.” In addition, Shepherd et.al. (2007) revealed that there were a total of 90 confirmed cases of dengue fever imported in the United States with one reported fatality in 1998. “The current estimate is 100 cases per year; however, the true number of dengue fever cases is believed to be higher because reporting is voluntary, many US physicians are not aware of dengue or its manifestations, and the manifestations are often nonspecific.” 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 The severity of the effect of this illness on people depends on a variety of factors such as: age of the patient, nutritional status, ethnic background, as well as “the sequence of infection with different dengue serotypes, virus genotype”( Shepherd et.al. 2007). In addition, the immediate diagnosis and quality of patient care largely affects the speed of recovery from this disease. The same study signifies that “the fatality rate in patients who met criteria for dengue hemorrhagic fever or dengue shock syndrome was approximately 6%. The mortality rate associated with dengue fever is less than 1%. “ Sex This virus affects both sexes, male and female. Age The dengue fever affects all people in various ages. Although there were some types that do not affect a certain age range, the other dengue types such as DHF and DSS affect even children below 15 years of age. In fact, there were some documented cases where dengue fever affected the whole family due to the Asian Tiger Mosquito’s feeding characteristic, to wit: “they inflict an innocuous bite and are easily disturbed during a blood meal, causing them to move on to finish a meal on another individual, making them efficient vectors. Entire families who develop infection within a 24- to 36-hour period, presumably from the bites of a single infected vector, are not unusual.” (Shepherd et.al. 2007) Clinical Symptoms A person afflicted with dengue fever exhibits the following symptoms: fever, headache, vomiting and nausea, skin rashes. Those not immediately diagnosed would have the following symptoms: bleeding from the nose or gums, abdominal pain, restlessness, fatigue, sore throat and cough. There are also incidences of dehydration associated with this illness. Close examination would reveal that there is a drop in platelet count in cases of DHF. Usually, 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.” (Shepherd et.al. 2007) Causes The medical research conducted by Shepherd et.al. (2007) simply and concisely state that “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 by the bite of an infected mosquito”. Treatment There are a series of treatment available for a person who contracted this illness. Combined medical care and drugs are utilized for the immediate recovery of dengue fever. If the person exhibits the symptoms indicated above, immediate consultation from a physician should be made. The first step for confirmation of this illness is the tourniquet test to determine if the person in positive with the virus. The decrease in platelet count should immediately be addressed. There might be incidence of dehydration associated with this illness that requires intravenous fluid administration. Usually, cases like these require hospital admission and patient care. According the Shepherd, et.al. (2007) “patients with dengue hemorrhagic fever or dengue shock syndrome may be discharged from the hospital when they meet the following criteria: Afebrile for 24 hours without antipyretics Good appetite, clinically improved condition Adequate urine output Stable hematocrit level At least 48 hours since recovery from shock Absence of respiratory distress Platelet count greater than 50,000 cells/μL” Medications For the treatment of dengue infections, medical studies reveal that there is no specific antiviral medication that is currently available. For symptoms like fever, the important thing to remember is not to give non steroidal anti inflammatory drugs (NSAIDs). Paracetamol can be given to treat fever and pain. For severe symptoms, the best remedy is to admit the patient in the hospital immediately so that all required medical interventions could be administered. Deterrence/Prevention Since no vaccine is available for the treatment of dengue fever, medical professions advise that the ultimate solution to prevent infection from this virus is to avoid being bitten by the Asian Tiger Mosquito. This can be done by following the enumerated measures, to wit: (Shepherd et.al. 2007) “Avoid travel to areas where dengue is endemic. This is not an ideal strategy because it would require a person to avoid most tropical and subtropical regions of the world, and many of these regions are popular travel and work destinations. Wear N,N-diethyl-3-methylbenzamide (DEET)–containing mosquito repellant. Wear protective clothing, preferably impregnated with permethrin insecticide. Remain in well-screened or air-conditioned places. The use of mosquito netting is of limited benefit, as Aedes are day-biting mosquitoes. Eliminate the mosquito vector using indoor sprays. Eliminate the breeding ground of the mosquitoes by not allowing them access to small accumulations of stagnant water around human habitats. Such accumulations can be found in pots, old tires, or any vessel capable of holding water.” CONCLUSION The Asian Tiger Mosquito has wrecked a number of lives due to the virus that it carries. When we think of it, do mosquitoes have any positive contribution to mankind? The answer lies in the food chain. Moquitoes benefit swallows, purple martins, bats, and some predatory insects. Other that those benefits, these insects are basically a menace to man. The significant issue that man is confronted is that having known what this type of insect can do, what havoc it can spread, more research and medical breakthroughs should be focused on preventing the spread of this disease. Starting with the factors that lead to this epidemic, man should be conscious of ensuring cleanliness in his environment. By eradicating the breeding places of these mosquitoes and by following the protective measures, one would have a greater chance of winning the war against this vector of disease – the Asian Tiger Mosquito. Works Cited Miller, S. & Harley, J. (2007). Zoology. McGraw Hill Companies, Inc. IntroduceSpeciesWHSAPBio. The Asian Tiger Mosquito. Retrieved on February 21, 2009 from Novak, R. (1992). The asian tiger mosquito, Aedes albopictus. Wing Beats, Vol. 3(3):5. Tenenbaum, D. (2002). Mosquito Bytes. Univesity of Wisconsin. Retrieved on February 25, 2007 from < http://whyfiles.org/016skeeter/> Crans, W.J. The Asian Tiger Mosquito in New Jersey. Rutgers Cooperative Extension Fact Sheet # FS845. Dorothy, J. Dengue (Break-Bone Fever). Retrieved on February 25, 2009 from Shepherd, S.M., Hinfrey, P.B. & Shoff, W.H. (2007) Dengue Fever. eMedicine: Infectious Diseases from webMB. Retrieved on February 25, 2009 from Read More