HIV and Transfusion Phylogeny and Transfusion Ariana Beck
HIV and Transfusion: Phylogeny and Transfusion Ariana Beck, M. D. PGY 3
Objectives ■ Introduction and background information • History of HIV and HIV phylogeny ■ ■ Current US HIV epidemiology and blood supply testing • CDC published data Current Global HIV epidemiology and blood supply testing • Focus on developing nations in sub-Saharan Africa
Introduction ■ ■ On June 5, 1981 Gottlieb et al from UCLA reported 5 biopsy confirmed cases of what at that time was called Pneumocystis carinii pneumonia at 3 different hospitals in Los Angeles, California Editorial note: “all the above observations suggest the possibility of a cellular-immune dysfunction related to a common exposure that predisposes individuals to opportunistic infections such as pneumocystosis and candidiasis. ” [Gottlieb MS, et al, CDC; 1981]
Introduction ■ With this first published case series in 1981, AIDS was recognized • Increasing numbers of homosexual men were diagnosed with rare malignancies and unusual opportunistic infections • The causative agent termed human immunodeficiency virus type 1 (HIV-1) was subsequently identified ■ ■ First published in 1983 In 1986, a morphologically similar but antigenically distinct virus was found to cause AIDS in patients in Western Africa • It was termed HIV-2 • Only distantly related to HIV-1 but closely related to a simian virus that was known to cause immunodeficiency in captive macaques [Sharp P, Hahn B; 2011]
Introduction: Taxonomy • HIV-1 and HIV-2 are encapsulated, positive sense, single strand RNA viruses • DNA intermediate during replication • Reverse transcriptase- lacks proofreading (thus high mutation rate) • Evolves at a rate of ~1 million times faster than mammalian DNA • According to the 2014 release from the International Committee on Taxonomy of Viruses, the family Retroviridae is actually not assigned to an order • The classification for viruses begins at order rather than kingdom and phylum as it does for cellular organisms • Spreads by mucosal surface exposure (sexual), perinatal, and percutaneous routes [He lio A et al; 2013]
HIV origins and phylogeny ■ Both HIVs are the result of multiple cross-species transmissions of simian immunodeficiency viruses (SIVs) that infect African primates • Most of these led to a limited extent of human spread [Sharp P, Hahn B; 2011]
HIV-1 origins and phylogeny ■ After the initial identification of the HIV viruses, subsequent studies identified additional related simian immunodeficiency viruses (SIVs) in various primates from sub-Saharan Africa • Thus far, these viruses are only found in African old world primates ■ The split between African and Asian primates is thought to have occurred 6 -10 million years ago • In native hosts, largely nonpathogenic ■ ■ In some mammals, these types of lentiviruses have infiltrated their hosts’ germlines to become endogenous “viral fossils” Additional evidence of co-evolution • The prevalence of naturally occurring SIVs varies widely in populations from 1% to 50% • These viruses cluster in a single phylogenetic lineage with HIV-1 and HIV-2 • The discovery of closely related viruses in chimpanzees led credence to theory that HIV emerged in humans as a result of zoonotic infection [Sharp P, Hahn B; 2011]
HIV-1 origins and phylogeny ■ Thus, due to its close relationship with HIV-1, SIV cpz (chimpanzee) is of great interest • Initially, it was thought that the prevalence of SIV cpz in wild populations is low ■ Due to low infection rates in captivated chimps • However, thanks to non-invasive serological and nucleic acid testing in fecal and urine samples, researchers were able to determine the true prevalence • Chimpanzees broken into 2 species ■ Common Chimpanzee (Pan troglodytes) • Further divided into 4 geographically differentiated subspecies ■ Western, Nigeria-Cameroonian, central, eastern ■ Additionally, the prevalence of SIV cpz in these populations varies widely from rare infection in some groups to 30 -50% infection rate in others ■ Bonobo (Pan paniscus) • This contrasts to other SIVs which are more homogenous in their distribution ■ In combination with the fact that only 2 subgroups are infected it follows that chimpanzees acquired the virus recently (at least after their divergence into subspecies) ■ Further studies suggest that SIV cpz is a complex mosaic of at least two SIV lineages • Part of the genome is closely related to SIV rcm (red-capped mangabeys) • Part is closely related to a clade of SIVs infecting several species including mona, spot-nosed, and mustached monkeys • Cross species infection likely occurred during predation! • This mosaic strain is the only known SIV strain in chimps [Sharp P, Hahn B, 2011]
HIV-1 origins and phylogeny ■ ■ ■ SIV cpz was originally thought to be harmless to its “natural” host • However, studies have shown 10 -16 fold increased mortality in aged matched controls • Necropsies show similar histopathologic findings to end-stage AIDs patients • This is in contrast to SIVs in sooty magabeys and Afican green monkeys which show no sign of disease despite high viral loads in blood and lymphatic tissues • Suggests that its natural history is different given its recent emergence and lack of time for coevolution SIV gor (gorilla) was also discovered using non-invasive fecal and urine testing • Lineage falls within radiation of SIV cpz suggesting cross species infection from chimpanzees • Likely resulted from a single transmission event 100 -200 years ago • Only found in west lowland gorillas and at low rates ■ Unclear if pathogenic due to lack of studies • Gorillas are herbivores so method of transmission is a mystery Why does all of this phylogeny matter? • Prior to these studies, it was thought that chimps were not a natural reservoir for SIV thus the source of HIV-1 was unclear • Understanding the natural history and evolution of these viruses is important [Sharp P, Hahn B, 2011]
HIV-1 origins and phylogeny • HIV-1 is broken into 4 different lineages M, N, O, and P • Each resulted from a single cross-species transmission event • Group M was discovered first and represents the pandemic form • Group O was discovered in 1990 • Represents less than 1% of global infections • Largely restricted to Cameroon, Gabon, and neighboring countries • Unknown source • Could be gorilla or chimp • Group N identified in 1998 • Even less prevalent than Group O • ~13 cases all from Cameroon • Group P was identified in 2009 in a Cameroonian woman living in France • Only identified in 1 other person living in Cameroon • Phylogenetic studies support a gorilla origin • Molecular clock studies suggest that M and O transmission occurred in the early twentieth century while groups N and P emerged more recently [Sharp P, Hahn B; 2011]
HIV-2 origins and phylogeny ■ ■ Largely restricted to West Africa • Highest rates in Guinea-Bissau and Senegal ■ Lower viral loads than HIV-1 ■ May explain lower transmission rates and extremely rare vertical transmission ■ Most individuals do not progress to AIDS • Those who do have identical clinical symptoms as HIV-1 • Different natural history ■ Largely being replaced by HIV-1 Originated in sooty mangabeys ■ Non-pathogenic in hosts • In fact, most prevalent in high-ranking breeding females ■ Hunted as pests in West Africa (likely source of transmission) ■ At least 8 strains identified (A-H) each from an independent host infection • Only A and B have spread within humans to a significant degree ■ A is found throughout West Africa ■ B is found predominantly in Cote d’Ivoire ■ Remaining strains considered dead-end transmissions [Sharp P, Hahn B; 2011]
HIV-1, HIV-2, HIV-1 O [Sharp P, Hahn B; 2011]
HIV-1 group M origin and spread ■ So how did HIV-1 group M become pandemic? There is substantial mystery and uncertainty in the early period of the HIV-1 pandemic ■ This group used statistical methods and sequencing data to reconstruct the early dynamics of HIV-1 establishment and transmission in the changing social landscape of what is now Kinshasa in the Democratic Republic of the Congo (DRC) and published their results in Science • Previous molecular clock studies have shown that the common ancestor of HIV-1 group M emerged in the first half of the 20 th century [Faria N, et al; 2014] ■
HIV-1 group M origin and spread • • • By the end of the 1980’s, the genetic diversity of HIV-1 group M in the DRC was the greatest in the world This group performed phylogenetic analysis of viruses collected both in the DRC and the Republic of Congo (RC) • The group M common ancestor was determined to have emerged around 1920 (95% Bayesian confidence interval 1909 -1930) • Historically, there are two sequences of HIV-1 that were isolated from blood and tissue samples collected in Kinshasa in 1959 -1960 • The group used one of these samples as a control and using their model correctly estimated the date of that sample at 1958 (95% BCI 1946 -1970) This modeling also confirmed Kinshasa as the epicenter of the pandemic • This is consistent with the observation that Kinshasa currently harbors the greatest genetic diversity on HIV-1 The initial cross species transmission predates the group M common ancestor and likely occurred in southeast Cameroon At that point, the virus most likely traveled by ferry to Kinshasa • During that time, Cameroon was a German colony and travel between Kinshasa and Cameroon was common and related to the ivory and rubber trade [Faria N, et al; 2014]
HIV-1 group M origin and spread • From Kinshasa, the virus spread to Braazaville (6 km distance) around 1937 • Reached Lubumbashi around 1937 and Mbuji-Mayi by around 1939 • It took another decade for the virus to seed central and northern DRC locations • Reached Bwamanda by ~1946 and Kisangani by ~1953 • Likely secondary to low travel rates between Kinshasa and Kisangani at this time • The proportion of viral lineage movements originating in Kinshasa steadily decreased by ~8% per year and by the 1980’s, 50% of dispersal events were seeded from secondary locations [Faria N, et al; 2014]
HIV-1 group M origin and spread • Recall that group O is non-pandemic and largely confined to west-central Africa • This figure shows that at first, group M underwent a slow phase of growth (similar to group O) • Largely confined to Kinshasa at that point • Growth rates diverged around 1960 • Slow growth rate of group O thought to be due to multiple factors including higher susceptibility to host proteins • At that point, group M began to outpace the population growth rate of Kinshasa • Use of unsterilized injections in STD clinics, as well as other factors, played a role • Virus expanded geographically and began to establish new subpopulations • Group M Subtype B (originated in Kinshasa) arrived in Haiti around 1964 • Return of Haitian professionals who worked in the newly independent Congo in the 1960’s • This subtype spread to the US • Subtype C spread within Africa and accounts for ~50% of HIV-1 infections worldwide • Likely originated in Mbuji-Mayi (world’s second largest producer of industrial diamonds) and spread with movements of migrant workers [Faria N, et al; 2014]
Current HIV epidemiology ■ US and Worldwide
Diagnoses of HIV Infection among Adults and Adolescents, by Transmission Category, 2013—United States and 6 Dependent Areas N = 47, 958 Note. Data include persons with a diagnosis of HIV infection regardless of stage of disease at diagnosis. All displayed data have been statistically adjusted to account for reporting delays and missing transmission category, but not for incomplete reporting. a Heterosexual contact with a person known to have, or to be at high risk for, HIV infection. b Includes hemophilia, blood transfusion, perinatal exposure, and risk factor not reported or not identified.
Trends in Age-Adjusted* Annual Rates of Death due to HIV Infection by Race/Ethnicity, United States, 1990− 2010 Note: For comparison with data for 1999 and later years, data for 1990− 1998 were modified to account for ICD-10 rules instead of ICD-9 rules. for ICD-10 rules instead of *Standard: age distribution of 2000 US population ** Hispanics/Latinos can be of any race.
Blood product HIV testing in the US ■ ■ The first case of possible transfusion transmitted AIDS was reported in CDC’s MMWR in 1982 Currently, blood in this country is screened through a layered approach • FDA requires both the use of a questionnaire and laboratory testing using serology and nucleic acid testing on FDA approved platforms ■ Questionnaire excludes higher risk donors ■ Nucleic acid testing was implemented in 1999 • This reduced the window period of infection prior to the development of detectable markers in blood from about 22 days to ~10 -15 days • There is still an “eclipse period” of acute infection before the development of a detectable concentration of HIV RNA ■ About 9 days based on limited data • FDA approved platforms can detect HIV RNA at a minimum concentration of ~5. 5 copies/ m. L ■ This can be done on individual specimens or pooled specimens ■ The number of specimens in a pool is dependent on manufacturer specifications ■ Pooled testing is slightly less sensitive than individual testing due to dilution ■ Pooled testing is more cost effective [Laffoon B, et al; 2010]
Blood product HIV testing in the US ■ In this country, the estimated risk of acquiring HIV from transfusion is around 1 in 1. 5 million • This is declined from a risk of 1 in 450, 000 -600, 000 donations in 1995 and increased from 1 in 2, 135, 000 donations in 2001 • Modeled on data from 2007 -2008 which takes into account the increasing incidence of HIV in among blood donors ■ ■ The most recent confirmed case of transfusiontransmitted HIV in the USA occurred in 2008 and was reported in the CDCs MMWR in 2010 Detected when a blood center in Missouri discovered that a blood component from a donation in November of 2008 tested positive for HIV by EIA, MP-NAT, and indirect immunofluorescence [Laffoon B, et al; 2010]
Blood product HIV testing in the US ■ The donor had previously donated in June of 2008 • In both June and in November, he reported no HIV risk factors on the routine screening donor questionnaire ■ In June his whole blood tested negative for HIV by EIA and his plasma tested negative by MP-NAT (pool of 16 donations) at a reference lab • A lookback investigation identified two recipients ■ ■ One cardiac patient received p. RBCs and died of cardiac causes 2 days later One renal transplant patient received FFP • This recipient tested positive for HIV with an RNA viral load of 7, 240 copies/m. L ■ ■ The donor was interviewed and reported that he was married but had sexual contact with both men and women outside of his marriage including before his June donation Sequencing at the CDC confirmed that the donor was the source of the recipient’s infection [Laffoon B, et al; 2010]
Blood product HIV testing in the US ■ Prior to this case, the last case of transfusion transmitted HIV occurred in 2002 [Laffoon B, et al; 2010]
Blood product HIV testing in the US ■ ■ ■ In this case, the collection occurred during the “eclipse phase” The questionnaire would have excluded this donor if answered accurately It is likely that transfusion-transmitted cases of HIV are under identified • This is based on the observation that fewer than the expected number of cases are identified ■ ■ ■ Maybe estimation of risk too high Recipient death can occur before the identification of HIV infection Poor recall by infected patients of prior blood product receipt Lack of testing of blood product recipients leads to under diagnosis Infection may be attributed to other risk factors [Laffoon B, et al; 2010]
Global epidemiology ■ ■ Developing countries have experienced the greatest HIV/AIDS morbidity and mortality with the highest prevalence rates occurring in sub-Saharan Africa. Most new infection also occur in this part of the world [WHO data; Sharp P, Hahn B; 2011]
WHO Data ■ According a WHO fact sheet (No 279), in 2012, 70% of countries had a national blood policy • 62% have legislation covering safety and quality of blood transfusion ■ 44% of low-income countries • The WHO recommends that all blood donations should be screened for HIV, hepatitis B, hepatitis C, and syphilis ■ 25 countries are not able to screen all donated blood for 1 or more of the above infections ■ Unfortunately, poor quality HIV test kits are often used and there is lack of quality assurance [WHO statement, 2006; WHO fact sheet, 2014]
WHO Data ■ Unsafe blood transfusions have contributed to the burden of HIV in sub. Saharan Africa • In 2005, the WHO estimated that blood transfusions were responsible for 5% of infections ■ ■ The risk of HIV infection from a contaminated product is markedly higher compared to other common routes of exposure • 95 -100% vs 0. 1 -10% for sexual contact Contributing factors include high transfusion rates especially in women and children, higher prevalence of HIV infection, and inadequate testing • Even in countries with established policies, HIV testing is done by serology which has a longer window period than NAT • Lack of quality-assurance of testing ■ ■ Due to shortages, paid donation and family donation is often relied upon An overall shortage of blood in conjunction with higher rates of severe anemia compounds the problem • This results from pregnancy related complications, malaria, parasitic infections, malnutrition, sickle cell disease [Lefrere JJ, et al, 2011; WHO statement, 2006; WHO fact sheet, 2014]
WHO Data ■ ■ “WHO recommends that all activities related to blood collection, testing, processing, storage and distribution be coordinated at the national level through effective organization and integrated blood supply networks. The national blood system should be governed by national blood policy and legislative framework to promote uniform implementation of standards and consistency in the quality and safety of blood and blood products. ” Easier said than done! [WHO fact sheet; 2014]
How often is HIV transmitted via transfusion in Africa currently? • Used the incidence of HIV infection in repeat donors to estimate rates and relative risk of transfusion-transmitted HIV in 5 countries in sub-Saharan Africa • The study sent questionnaires to main blood banks of the participating countries • Presumed that a portion of these repeat donors had blood collected in the window period of their infection [Lefrere JJ, et al, 2011]
What happens in developing countries? ■ In most developing countries in Africa, blood transfusion systems are decentralized through individual hospitals • Blood is often obtained from family members and friends of the patient • Infectious testing is performed at the individual hospitals [WHO; 2014; Kongnyuy E, van den Broek N; 2007]
What happens in developing countries? ■ ■ The country of Malawi formed a national blood service in 2003 in response to the WHO blood safety initiative started in 2000 In Malawi, the Malawi Blood Transfusion Service (MBTS) provides 2/3 of blood while the decentralized hospitalized system provides 1/3 • Both test for HIV, hepatitis B, and syphilis ■ The MBTS also test for hepatitis C and malaria (via a blood smear based screen) • HIV testing is done using an ELISA based assay testing for the p 24 antigen and HIV-1 and HIV-2 antibodies ■ Hospitals use a rapid test for HIV and do not routinely test for hepatitis C or malaria • This system also does not test for the p 24 antigen thus enlarging the window period [Kongnyuy E, van den Broek N; 2007]
What happens in developing countries? ■ ■ ■ There are many challenges to the MBTS High overall HIV prevalence (~12% in general population) • Difficult to maintain and recruit donors ■ Only low risk donor groups identified are young males and students Storage and transportation Expense • Blood from the MBTS is more expensive than from the decentralized system • US $56 vs US $16. 28 Funding • The European Union initially funded the MBTS from 2001 -2006 • After 2006, the Malawian government and other partners had to take over In addition, there is poor communication between the MBTS and hospital based system [Kongnyuy E, van den Broek N; 2007]
What happens in developing countries? ■ ■ This highlights the difficulty in forming a nationalized blood service/ policy in developing countries However, since the implementation of the MBTS there was a 60% decrease in mortality among seriously ill children and a 50% decrease in mortality among pregnant women with severe blood loss ■ Not necessarily due to infectious disease/ HIV testing but the overall formation of a national service with appropriate standards which increased the availability, quality, and safety of blood [WHO statement, 2006; Kongnyuy E, van den Broek N; 2007]
Conclusion ■ ■ In conclusion, we have learned a lot about HIV in the years since its recognition Blood safety has come a long way in this country • Continues to evolve and improve in developing countries [Kongnyuy E, van den Broek N; 2007]
References ■ ■ ■ M. S. Gottlieb, et al. ; Centers for Disease Control (CDC), MMWR Morb. Mortal. Wkly. Rep. 30, 250– 252 (1981). <http: //www. cdc. gov/mmwr/preview/mmwrhtml/june_5. htm> He lio A. Toma s, Ana F. Rodrigues, Paula M. Alves and Ana S. Coroadinha (2013). Lentiviral Gene Therapy Vectors: Challenges and Future Directions, Gene Therapy - Tools and Potential Applications, Dr. Francisco Martin (Ed. ), ISBN: 978 -953 -51 -1014 -9, In. Tech, DOI: 10. 5772/52534. Available from: http: //www. intechopen. com/books/gene-therapy-tools-and-potential-applications/lentiviral-gene-therapy-vectors-challenges-and -future-directions Sharp PM, Hahn BH. Origins of HIV and the AIDS pandemic. Cold Spring Harb Perspect Med. 2011 Sep; 1(1): a 006841. doi: 10. 1101/cshperspect. a 006841. Review. Pub. Med PMID: 22229120; Pub. Med Central PMCID: PMC 3234451. ■ The Centers for Disease Control and Prevention (CDC) ■ The World Health Organization (WHO), Fact sheet No 279, updated June 2014. ■ B. Laffoon, et al. ; Centers for Disease Control (CDC), MMWR Morb. Mortal. Wkly. Rep. 59, 1335 -1339 (2010). ■ ■ ■ E Kongnyuy, N van den Broek. Availability of blood for transfusion in maternity units in Malawi. The Internet Journal of Third World Medicine. 2007 Volume 7 Number 1. http: //www. unaids. org/sites/default/files/en/media/unaids/contentassets/documents/countryreport/201003_MOT_West_Africa_en. pdf Lefrère JJ, Dahourouh H, Dokekias AE, Kouao MD, Diarra A, Diop S, Tapko JB, Murphy EL, Laperche S, Pillonel J. Estimate of the residual risk of transfusion-transmitted human immunodeficiency virus infection in sub-Saharan Africa: a multinational collaborative study. Transfusion. 2011 Mar; 51(3): 486 -92. doi: 10. 1111/j. 1537 -2995. 2010. 02886. x. Epub 2010 Sep 28. Pub. Med PMID: 20880002.
WHO Data [WHO fact sheet; 2014]
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