This paper reviews how and what are the factors taking to the rapid transmittal and spreading of HIV throughout the planetary until become the monumental challenge to planetary public wellness where the entree to intervention is highly limited and under research. The challenges faced in bring forthing the effectual vaccinums are besides being highlighted in this paper.
Acquired Immunodeficiency Syndrome ( AIDS ) started to emerge in the human population on 1981. To day of the month, there is concrete grounds turn outing that AIDS has characteristic and2 its aetiologic agent, the human immunodeficiency virus ( HIV ) able to traverse the simian-human species barrier ( Korber et al. 2000 ) . The spread of HIV among the human population is due to insecure injection, heterosexual and homosexual intercourse, and transfusion patterns in worldwide, enabling the virus to accommodate to worlds through mutant and consecutive transitions.
Today, HIV/AIDS is the taking cause of decease in sub-Saharan Africa and the 4th biggest slayer in the universe. An estimated of 14,000 people/day become septic with HIV, with more than 95 % of them populating in under-development parts of the universe ( UNAIDS 2008 ) . As deathly AIDS remain incurable and HIV causes the disease to distribute non-stop, wellness governments, authorities, non-governmental or administrations, sociologists, wellness pedagogues and assorted health-related research workers are reappraising the bing methods of bring arounding the slayer disease. In the country-country analyses of AIDS spread carried out by joint venture of United Nations and World Health Organisation ( WHO ) , it had proven that the rate of deathly infection spreading is serious. As a consequence of that, the development of a safe, effectual and low-cost vaccinum is desperately needed. The first stage test on HIV vaccinum was conducted in USA in 1987. Following, more than 35 vaccinums were being tested in over 65 Phase two/three clinical tests which involved more than 10,000 healthy voluntaries from more than 10 states ( Girard et al. 2004: 1221 ) . Two stage tests have been done to completion ( Cohen 2003 ) and 3rd one is still under advancement ( McNeil et al. 2004 ) . However, the most effectual HIV vaccinum is still exposed due to multiple challenges. The failure of developing an effectual vaccinum is due to the high familial variableness of the viral ( Korber et al. 2001: 41 ) , deficiency of cognition of the virus ( Lifson et al. 2000: 2584 ) , the trouble of bring forthing loosely neutralizing antibodies ( Burton et al. 2004: 223 ) and the complexnesss of the developing a large-scale clinical trial tests in developing states ( Excler et al. 2000: 210 ) .
The scientific inquiries sing HIV vaccinums tests are complex. HIV vaccinum research faces more and larger challenges compared to other vaccinums such as Polio virus, H1N1 pandemic flu virus and so forth. Unlike other viruses with successful vaccinums, HIV can be in the host as free virus every bit good as infected cells ( Savla 2004: 146 ) . This is the most hard portion of happening the solution. The HIV targets the immune system itself by integrating its familial stuff into the host cell and reproduce new cells incorporating the HIV cistrons itself, therefore the HIV reservoirs in other cells harbour integral viruses that can stay undetected by the immune system ( Moodie et al. 2006: 148 ) .
The paper begins by briefly foregrounding the history of the HIV and how it spreads to worldwide until go a planetary serious issue. Review of the current advancement of HIV/AIDS vaccinum research and development, and the challenges will besides be discussed.
How large is the job?
To day of the month, there are about 33.2 million individuals are presently populating with HIV infection worldwide including 15.4 million adult females and 2.5 million kids under 15 old ages old ( UNAIDS/WHO 2007 ) . In the twelvemonth 2007, there were 2.1 million grownups and 0.4 million of kids freshly infected, and 2.1 million died from HIV infection. Sub-saharan African states is accounted with the highest HIV/AIDS instance, whereby 67 % of all people populating with HIV. Other of import parts affected by HIV include the Caribbean, Latin America and South and Southeast Asia ( Moodie et al. 2006: 148 ) . In many African states, the overall HIV prevalence in the grownup population can be greater than 10 % . Among the most severely hit states are South Africa, with more than 5.6 million people got infected ( Bure et al. 2002 ; 2011 ) . As in many other countries, Asia shows highly diverseness in its HIV cuticles, both geographics and temporally. Cambodia, Burma, Thailand and some provinces like India are those where HIV hit early and difficult, where the grownup HIV prevalence now exceeds 1 % while Bangladesh, Laos, Philippine and South Korea are those holding really low degrees of infection ( Ruxrungthan et al. 2004: 369 ) . Based on projections of economic and societal development and increased bar activities, HIV/AIDS deceases are projected to increase to 3.7 million in 2030 ( Mathers and Loncar 2006: 442 ) . Besides that, Mathers and Loncar ( 2006: 442 ) besides stated that HIV/AIDS transmittal will brace in higher income states or to diminish in the following decennaries, but will still remains as a serious job in low income states.
Theories of the beginning of HIV/AIDS
Since the eruption of the epidemic, there are many arguments around on the theory of the beginning of the HIV/AIDS. However, there is a danger in placing the right theory of the beginning of the HIV/AIDS because some people will utilize the argument to set fault on a peculiar group of persons ( Adesoji 2005 ) . In order to explicate this affair, Adegbenjo ( 2001 ) stated that the first instance of HIV/AIDS occurred in the United States in the early 1980s, but there is deficiency of beginning sing the beginning of the disease. Below are some of the theories of HIV/AIDS epidemic outgrowth.
The Chimpanzee Theory
HIV is a portion of the household of viruses called Lent viruses and other than HIV, they have been found in a broad scope of human Primatess ( Adesoji 2005 ; 42 ) . The others viruses are known as simian ( monkey ) immunodeficiency viruses ; a inferior character is used for denoting their species of beginnings ( Fritzen 2000 ) .
Harmonizing to Kanabus and Allen ( 2001 ) , the HIV is by and large being accepted as the descendent of the SIV virus because some of the SIV bear a really close resemblance to the HIV virus particularly the HIV-1 and HIV-2. Although it is believed that the Pan troglodytess are responsible to convey the virus to human, it is still assumed that homo was affected by an unidentified 3rd party ( Adegbenjo, 2001 ) .
Another suggestion by the research workers is that the human must hold killed the Pan troglodytes and eat the meat, therefore doing the virus to be transmitted into the human organic structure ( Adesoji 2005 ; 43 ) .
Polio Vaccine Theory
Harmonizing to this theory, Dennis Hooper postulates that worlds in the early testing on infantile paralysis vaccinum in Africa in the 1950s indirectly brought the HIV virus into human ( O’Neil 2000 ; 1051 ) . It suggests that an unwritten infantile paralysis vaccinum must hold been manufactured from contaminated Pan troglodytes ‘s kidney tissue that was later introduced to the African human population ( Fritzen 2000 ) . Although the Hooper ‘s theory is non scientific, but the clip and the earliest instance of the AIDS and the testing of vaccinum coincide with each other, and if Hooper is right, when the homo consumed the vaccinum, the virus must hold entered into the human blood watercourse and evolved into HIV-1 ( Adesoji 2005 ; 43 ) .
The Pathogenitical Transfer Theory
Besides the two possible theories mentioned above, another controversial theory is HIV was transmitted iatrogenically or in simple words via medical experiments. One celebrated theory is the polio vaccinum theory which causes the virus to be transferred. However, this theory was objected by Chireshe and Chireshe ( 2003 ; 25 ) .
Chireshe and Chireshe ( 2003 ; 25 ) has identified three of the earliest known cases of HIV infection. The first statement is a plasma was taken in 1959 from an grownup adult male in what is now the Democratic Republic of Congo. The 2nd statement is HIV found in the samples from an African American adolescent who died in St. Louis in 1969, and the 3rd statement is HIV was found in the tissue sample from a Norse crewman who died around 1976.
The advocate of the confederacy theory is John S. James ( O’Neil 2001 ; 1051 ) . This theory positions AIDS as a arm developed by person ‘s source warfare experiments and released by chance or intentionally ( Adesoji 2005 ; 43 ) .
Factors involved in the spread of the HIV/AIDS
A figure of factors are involved in the spread of the virus and below are some of the factors highlighted by some of the research workers ( Adesoji 2005 ; 44 ) .
Because sexual intercourse is the chief beginning of the spread of the HIV/AIDS, a deficiency of the clear moral criterions obviously promotes the spread of the virus. This analysis appears to be confirmed by the behavior of immature people. For illustration, a study in one state indicated that about a 3rd of young persons aged between 12 and 17 had engaged in sexual intercourse ( Adegbenjo, 2001 ) .
Sexually Transmitted Disease
The presence of a sexually transmitted disease ( STD ) increases the hazard of HIV infection. Research consequences had shown that STD are common in the young person and there is a high inclination that people who suffer STD are likely to be prone to HIV/AIDS ( Chireshe and Chireshe 2003 ; 25 ) .
Many hapless states are combating for poorness particularly Africa has created a clime favorable to the spread of the HIV/AIDS. Many occupants encounter malnutrition job and the deficiency of the medical installations. These factors are lending to the spread of the viruses ( Adesoji 2005 ; 44 ) .
A big figure of those infected by the disease are non cognizant of it. They prefer non to be tested clinically because of afraid of losing friends, household and their occupation as people will turn away from them one time they have been confirmed to incorporate HIV/AIDS inside them ( Chireshe and Chireshe 2003 ; 25 ) .
Epidemiologic forms of HIV infection and transmittal
Basically, epidemiologic, socio-demographic, behavioral, and biological factors can lend to the spreading and transmittal of HIV. The character of each sub-epidemic remains mostly determined by the extent to which people are exposed to HIV by manners such as: ( 1 ) sexual intercourse ( vaginal, anal and unwritten ) ; ( 2 ) injection ( sharing of drug injection equipment ) , transfusion or organ transplant of HIV infected blood or variety meats like liver organ transplant, and ( 3 ) maternal-infant, from a adult female to her fetus or baby ( Opuni and Bertozzi 2004: 1013 ) .
Epidemiology by part
It is good known that Africa is the part with most badly HIV/AIDS epidemic. At the terminal of 2002, 29.4 million people populating with HIV/AIDS in sub-Saharan Africa and the part histories for three-fourthss of the 20 million people that have already died ( Opuni and Betozzi 2004: 1015 ) . Heterosexual HIV transmittal is the major factor lending to the spread among grownups, with really small transmittal recognised from homosexual intercourse or shooting drug usage ( Chireshe and Chireshe 2003 ; 25 ) . Harmonizing to Opuni and Betozzi ( 2004: 1015 ) , an estimated of 2.6 million kids under 15 old ages old were populating with HIV/AIDS in sub-Saharan Africa by the terminal of 2001.
Asia and Pacific
Harmonizing to Opuni and Betozzi ( 2004: 1015 ) , there was about 1.2 million people were populating with HIV/AIDS in East Asia and Pacific by the terminal of 2002, in which 6 million of people were found in south and southeast Asia. Factors such as cross-border opiate traffic between states, drug usage affecting sharing of injection equipment and the sex trade are factors taking to the spread of HIV in this part.
Surveies in China have shown that shooting diacetylmorphine users in western Yunnan state ( Beyrer et al. 2000: 78 ) and addition of sexual familial disease are factors of rapid HIV transmittal in China ( Chen et al. 2000: 140 ) . Commercial sex is besides one of the grounds taking to the rapid spreading of HIV particularly in Thailand. The many work forces, who were infected by sexual contact with cocottes, transmitted HIV in bend to their other female sex spouses ensuing in a subsequent addition in maternal-infant HIV transmittal ( Nopkesorn and Mastro 1993: 1235 ) .
Latin America and Caribbean
By the terminal of 2002, it was estimated that 1.5 million grownups and kids populating with HIV/AIDS in Latin America and Caribbean ( Opuni and Betozzi 2004: 1015 ) . The rapid dispersed transmittal of HIV/AIDS is due to homosexual and bisexual among work forces particularly in Brazil ( O’Neil 2000 ; 1051 ) .
Europe and Central Asia
Survey by Opuni and Betozzi ( 2004: 1015 ) indicates that there were about 570,000 people populating with HIV/AIDS in Western Europe by the terminal of 2002. Groups preponderantly affected in Western Europe are homosexual and bisexual work forces and shooting drug users with really low rates among straight persons in the populations.
HIV virus is a lentivirus from the household Retroviridae. It can be seen as biological nanostructure ( about 100-150 nanometer ) , consists of a host-derived membrane, a nucleocapsid and familial stuff in the signifier of RNA incorporating three construction cistrons ( Levy 2009: 148 ) . These cistrons codification for of import group specific antigens, indispensable viral enzymes and the two glycoproteins present in the outer viral membrane, viz. gp120 and gp41, are responsible for recognizing the CD4 receptor cell and the CCR5 or CXCR4 co-receptor of the host cell membrane, and for the virus cell merger ( Nevas et al. 2010: 459 ) . As a consequence of changeless transcript mistakes, these viral constructions have high polymorphism which will take to mutant, therefore ensuing in antiretroviral-resistance development.
There are fundamentally two types of HIV, viz. HIV-1 and HIV-2. HIV-1 is phylogenetically close to SIVcpz which is a commensal virus in Pan troglodytess, and could be due to the individual transmittal event from Pan troglodytess to human, whereas the HIV-2 strain is closely related to SIVmac which is the aetiologic agent of simian AIDS, a commensal virus in coal-black mangabey monkeys ( Adegbenjo, 2001 ) . HIV-1 is farther subdivided into three major groups, they are M ( major ) , O ( outlier ) and N ( non-M or non-O ) . The bulk of HIV-1 strains doing the planetary AIDS pandemic belong to type M, which has evolved from human to organize at least 10 familial subtypes, besides known as clades, indicated by alphabetical letters from A to K ( Tatt et al. 2001: 60 ) . HIV-1 subtype B is the one predominates in Latin America and the Caribbean. Subtype A and D are found in Central Africa while subtype C are accounted for the bulk of infections in southern Africa, eastern Africa and India ( Tatt et al. 2001: 60 ) . Antibodies that are specific for isolates from one patient are non capable to recognize isolates from other patients even though it is within a given subtype. Because of this, HIV strains can recombine and organize mosaic viruses called Circulating Recombinant Forms ( CRF ) which in bend can derive epidemiological laterality ( McCutchan 2000 ) . The aminic acids sequence of the viral envelope glycoprotein shoes up to 25-35 % divergency between different subtypes and up to 20 % divergency within any given sub-type causes a challenge to vaccine development ( McCutchan 2000 ) .
Challenges and troubles of developing HIV vaccinums
Natural infection with HIV does non ensue in virus clearance by the host immune system and the development of natural unsusceptibility to re-infection. HIV is able to defy obliteration and continues consuming CD4+ T cells which finally leads to clinical patterned advance to AIDS. HIV-1 is able to incorporate as a latent proviral DNA into the genome of durable memory CD4+ T cells, which in bend provide a relentless reservoir of the virus that escapes immune surveillance. The window of chance for an HIV vaccinum is hence narrowly limited to the really early phases of infection, before the virus can seed the lymphoid variety meats in mucosal tissues ( Peterlin and Trono 2003: 103 ) .
Besides that, HIV is besides able to develop multiple mechanisms to besiege the host immune responses including its ability to impact the major histocompatibility composite ( MHC ) category I molecules and understate its acknowledgment by CTL, every bit good as its high familial development rates allows it to hedge immune responses through the outgrowth of viral CTL ( Evans and Desrosiers 2001: 150 ) . Another trouble with the development of an effectual HIV vaccinum is that the virus is envelope glycoprotein is able to hide its conserved receptor and co-receptor binding sites in crypts that are masked by the hyper-variable cringles of the molecule and by glycan residues ( Girard et al. 2004: 1221 ) . Neutralizing antibodies induced are chiefly targeted to the hyper-variable cringles of the molecule and they seldom recognise the receptor binding sites, which makes it hard to bring forth loosely cross-reactive neutralizing antibodies against primary virus isolates from patients ( Yang et al. 2004: 12981 ) .
To day of the month, multiple vaccinum constructs and inoculation schemes have been tested, including DNA vaccinums, fractional monetary unit vaccinums, live vectored recombinant vaccinums and assorted prime-boost vaccinum combinations.
The HIV pandemic is now come ining the 3rd decennary. Large parts of Africa have already been affected by the epidemic and in future will convey an increased load of AIDS-related decease. Asia, place to half of the universe ‘s population, will be an of import part in the AIDS epidemic in this following millenary. In many states, AIDS will probably go the prima cause of decease in grownups and one of the prima causes of baby and child mortality. Further research informations is of import in tracking the HIV epidemic, directing bar activities, and steering research. What is missing now is the information on the forms of hazard behavior. Research in this country has to pay more accent on the virus behavioral features and bar steps. A system that is able to compare biological and behavioral informations for maximal explanatory power and adapt to the altering demands of epidemics is of import to bring forth quality informations that addition and better the national responses.
To day of the month, many research advancements have been done to do a better apprehension of the complex interaction between HIV and the host immune system. This has led to the development of new, powerful antiviral drugs able to command the virus reproduction. However, there are still many basic inquiries still remain unreciprocated, including designation of protective immune mechanisms, turn toing the high variableness of the virus and its ability to hedge immune responses. The current viral research suggests that an effectual vaccinum need the ability to bring on both neutralise antibodies and cell-mediated unsusceptibility. One of the challenges for HIV vaccinum development is to understand how to plan envelope immunizing agents to efficaciously arouse the high variableness of the virus. Among the challenges in the development of HIV vaccinums is the deficiency of scientific cognition on the nature and degree of the immune responses required to protect against HIV infection and development of the disease. Therefore, the most of import facet of HIV vaccinum research is to analyze the effectual response of both weaponries of the immune system.