Evaluation of Current Techniques in Diagnoses of Human Immunodeficiency Virus (HIV)
Chapter One
AIMS AND OBJECTIVES
To evaluate the current techniques used in the diagnosis of Human Immunodeficiency Virus (HIV).
To help recommend the best and most reliable one essaying HIV.
CHAPATER TWO
LITERATURE REVIEW
Pathogenesis of HIV infection
Progression to AIDs proceeds through relatively distinct clinical state in HIV infection. The maiden clinical infection is always associated with symptoms, which are typical for viral infection in general spantaneous viral replication presumable occurs during this initial infection and the CD+4 cells which have markers such as helper T-lynphocytes get preferentialy infected (Levy, 1997).
Seroconversion leads to an Immune response to HIV-I and as such, the initial infection ends and an esymtomatic periods of clinical latency follows. Thlatency period which follow before the manifestation of AIDS are variable. The variable in some cases cuts across age. Manifestation is faster in cildren and older peple and relatively delayed in adults, young and adolescents. The diagnosis of AIDS is synonymous with short life expectancy. It is believed that acute infection may present an illness manifestation within two (2) to six (6) weeks after HIV infection. This may occur in 53-93 percent of adults with HIV infection. At this periods the degree of HIV replication are welled controlled.
Finally, after incubation period, then there are an increase rate of HIV replication and Immune system breakdown due to a significant decline in CD4 T-lymphocytes cell count, these factors as believed to activate HIV- infected cells and could also stimulate HIV replicating, the base problem of HIV infection is the presence of HIV in T-lymphocytes and monocytes which can be activated by foreign ankigers in the body and also by infections agents. The activation heads ato HIV expression and replication due to additional T-lymphocytes and monocytes begin infected, and subsequently activated (Jonathn, 1992).
Epidemiology of HIV
This could be used to understand the spead of HIV, over 20 years, since it was first indetified the HIV/AIDs epidemic has continued to exceed all expectation.
HIV disease spreads mainly by sexual intercourse, sharing of hypodermic needable or from mother to unborn baby. Promsevous homosexual man were the hit by the epidemic. An estimated 1.4% to 10% of American men are active homsexual. A survey done before the arrival of AIDS found that 33% to 40% of gey gays had more than 500 lifetime sexual partners. 4.5% of one group of gay men in senfrancisco were infected with HIV by 1984. The pace of the epidemic among gay men has reduce slowly but still, there are more than 22,000 new Aids cases reported heterosexual spread of HIV is increasing and promise to be the dominant mode of transmission as it is in many African countries. Sex with multiple partners; begin the receptive partners, especially receptive anal sex, traumatic sex and any irritation or inflammatory process as from another sexually transmission disease all increase the risk of sexual HIV transmission.
The next most important mode of transmission of HIV is through blood and blood products. Individuals infected with HIV who donates blood before any screening test became available in 1985, Unknowingly infecting thousand of transfuser recipients, transmission by blood is still a major factor in the HIV disease pandemic, because of sharing of needles by those who abuse injected drugs.
Another important mode of HIV, spreads is from mother to infant tranmission. Women represent an increased percentages of the total AIDs cases as hetro sexual spread of HIV increases. An estimated 60% of new AIDS cases in women in 1998 were acquired from hetrosexual contact with infected person and an estimated 70% of new HIV infection. If untreated about one out of every Ten pregnant, HIV positive women will miscarry and of liveborn babies, 20% to 45% will develop AIDS. Breast feeding carries a significant risk of mother- infant transmission (Tello et al, 1998).
Transmission of HIV
Human immune deficiency virus (HIV) is transmitted through sexual contact, both the homosexual, Bisexual and hetetrosexual. Parenteral transmission occurs largely among intravarous drug abuser. It is also transmitted by transfussion of infected blood of HIV and mothers to their infants during child birth (Ukaejiofofo, 1996).
CHAPTER THREE
MATERIALS AND METHODS
Current Diagnosis of HIV infection
HIV is a very insidious virus which remains unnoticed for months or years before manifestation. This of course is the reason which led to the diagnosis of the virus at as very later stage prior to this period. But presently, since the awareness that the manifestation of HIV is hinged around opportunistic infections; it is quite easy and faster to suspect and diagnose the scourge of the human race. Again, the diagnosis of HIV infection and manifestation is a function of the manifesting opportunistic infections.
Patients presenting for HIV serology are initially interviewed by a medical officer for <STD>, sexually transmitted disease, including HIV infection, risk assessment and appropriate test, involves taking a detailed sexual and blood exposure, the patient have experienced. It is therefore adviseable that all patients who are at risk of HIV should be informed about other sexually transmitted disease (STDs) and be offered testing for these such as syphilis. When a virus enters a person’s body, the immune system begins to make antibodies, it takes six 6 weeks for a person to make antibodies to HIV. During the window period of a person recently infected with HIV can still have a negative result. Antibiotics are used in two (2) common test for HIV; the Enzymes linked – immunosorbent assay (Elisa) and eastern blot (10B), each test has its benefits and draw backs because of this, they are usually used together (Feorino et. Al., 1999.
Following the diagnosis, HIV tests are done. After counseling and the blood is sent to the laboratory. It should be emphasized that only through serology can we test HIV. In the laboratory the serological method emphasized in the. Enzymes linked – immunosonbent assay, Elisc, screening HIV is performed. There are various Elisa methods such as the Hi tech., Quickspot test. Where the Elisa test is positive, a confirmatory test is carried out with the western blot test (WB). However, this goes to point that the Elisa test cometimes are not valid without the western blot confirming. <Baruch 1999).
CHAPTER FOUR
RESULT
Elisa are the most frequently used methods for screening blood samples for HIV antibody. The sensitivity and specificity of the presently available commercial systems approached 97% but false positive and false negative reaction occurs. It must be confirmed with a second test called the western blot which is a more specific test and will confirm, if someone is truly HIV positive, as there are other condition which may give a false positive Elisa screening test (eg lupus, Lyme disease, syplilis).
CHAPTER FIVE
Discussion and conclusion
Patients blood samples were collected in the university of Nigeria teaching hospital Enugu and was diagnosed with Elisa, Western blot and redioimmunoassay. The blood serum were used for the diagnosis, it was found out that patients both male and female of different age range were negative and 51 patients comprise of male and female of different age range were positive, after the4 confirmatory test, of all Elisa positive test.
The third table shows the numbers of positive result with their percentage both sexes. The percentage of male patients were low to compare to the one of the female patients, the male were 39.2% whereas female patient were 60.8%. the fourth table shows the number of negative result of patients with their percentage. The percentage of the female with negative result were higher than the male patients, the female were 55.8% while the male are 44.2. There is no much different in the negative result to compare to the positive result of the bsoth sexes.
Finally, the fifty table shows the rate of infection among the study group, the sample examine, number of patients with positive result and number of patient with negative result 51 and 54 respectively. The piechart represent the illustration fo the rate of infection among the study group, with positive 51 and negative 154 with the sum total of 205 of the patients, patient with positive results are 89.60c and those with negative results are 270.40c
CONCLUSUION
The ultimate consequence of HIV infection is death. At the very emergence of this infection which lead to the birth of AIDS – acquired immune deficiency syndrome, death tolls were unchecked and staked were uncontrolled table. The unremitting effort and research by these scientist. Dulbecco et al have resulted in the capacity to put the ultimate consequence at bay for sometime and thereby increasing longerity.
The pathogenesis of how HIV infection begins are in similar to every other known infection common in our societies. But the difference is that of prolong circumstance which defy known cases of effective therapy. Although reasonable strides have been achieved in the regulation of HIV infections these strides have been, so achieved due to the understanding of the nature of HIV, which has shown high rate of mutation of the qenes, which has resulted in the strains of HIV.
There is no known cure for this infection leaves it, it’s epidemiology to be known both consciously and unconeously. In Aiss case, the pre-condition still remain as the blood, semen, or vaginal fluid of an infected person coming in direct contact with that of an uninfected person. So it is best to avoid blood contact on any blood stained object, practise safe sex, Any HIV carriers should be remind that he or she are not reliable to donate blood.
Following the potential sequence of the practice and observation carried out on patients (UNTH) shows how the sensitivity of Elisa kit worked, it’s fastness to analyze a large sample fast and the western blot was used as confirmatory test to Elisa. Two hundred and five patients were diagnosed, and one hundred and fifty-four were Negative and only fifty-one of the remaining are positive.
The evaluation of current techniques used in the diagnosis, show how the Elisa complete it’s analysis for 12-13 minutes, western blot as confirmatory test and the most accurate takes 2-5 minutes to complete it’s analysis. Radio-immunoassay take a long time to complete it’s analysis, because a lot of step are involved, it can be incubated for 2-3 days or for 72 hours to complete. It’s testing stage.
The three techniques are more reliable for the diagnosis of HIV virus, then any other techniques used
Recommendation
The Elisa kit can be recommend for the diagnosis of Human immunodeficiency virus (HIV) because of it’s specific and sensitivity to both antigen and antibody. It analyze very fast, Elisa has a good ability to detect antibodies. It is a basic quality of any medical laboratory test. Its limitation is that it can give false positive result, which can be confirmed with the use of western blot. To avoid such occurrence, most clinic and blood bank run a second test on serum that is positive, using another Eluisa kits.
The western blot also look for antibodies to HIV, it is not as sensitive as the Elisa test but it is able to detect more close at whet kind of antibodies present. When a Western blot is positive, it is specific because, it detect antibodies to a specific disease.
To avoid one contacting HIV, it is better to stay clear from the use of sharp object stained with blood, avoid sex with multiple partners and try to zip up to avoid other sexually transmitted disease associated with HIV.
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