2. Introduction
◦ Emerging infections- defined as ‘those whose incidence has increased within
the past two decades or threaten to increase in the near future’.
◦ Emergence may be due to
the evolution of an existing organism
the spread of a new agent
the recognition of an infection present in the population but has gone undetected
the reappearance of a known infection after a decline in its incidence.
5. Dengue
◦ Caused by- four arboviruses (DENV 1–4) belonging to the Flavivirus genus.
◦ Transmission- primarily by Ae. aegypti mosquitoes, Ae. albopictus is also a competent vector.
◦ Symptoms- wide range of outcomes, from asymptomatic infection to a fatal shock syndrome. Presents
with onset of fever, rash, a severe headache, lumbosacral aching pain followed by muscle pain, bone
pain, anorexia, nausea, vomiting, and weakness.
◦ Incubation period- 4 to 7 days following the bite of an infected mosquito.
◦ Diagnosis- NAT or viral antigen testing
◦ Treatment & Prevention- Vaccines are in clinical trials. No definitive management, only supportive care.
◦ Donor deferral- for 6 months
6. HTLV-I/II
◦ Causative agent of adult T-cell leukemia
◦ Prevalence- in Japan and The Caribbean.
◦ Has been associated with a neurological disorder called HTLV associated myelopathy
◦ Prevalence- among intravenous drug users
◦ Transmission- via infected lymphocytes
◦ Transmitted vertically (breastfeeding), sexually (transmission from male to female more common), and
parenterally (blood transfusion or IV drug abuse).
◦ Screening for HTLV-I began in 1988; a combined HTLV-I/II assay was approved 10 years later in 1998.
◦ Diagnosis- IFA and Western blot
7. HTLV-I/II
◦ Treatment- does not respond well to chemotherapy; mean survival time with acute ATL is <1 year.
However, early treatment with corticosteroids appears to have some effect
◦ Donor criteria- There is no approved protocol for donor re-entry involving HTLV-infected donors
8. West Nile virus (WNV)
◦ single-stranded RNA lipid-enveloped virion
◦ Prevalence- common in S. Africa, Europe, N. America & West Asia
◦ Host- arthropod-borne virus involving the natural reservoir host (birds) and the
intermediate host (mosquitos), which can infect a human.
◦ first detected in the United States in 1999
◦ Symptoms- symptoms ranging from mild fever and headache to extensive rash, eye
pain, vomiting, inflamed lymph nodes, prolonged lymphocytopenia, muscle weakness,
disorientation, and even acute flaccid paralysis and poliomyelitis. The association of
paralysis and poliomyelitis with WNV is recent.
◦ Incubation period- 3 to 14 days following the mosquito bite
9. ◦ WNV is capable of crossing the blood-brain barrier and can cause what is known as
West Nile encephalitis, West Nile meningitis
◦ Testing for WNV began in 2003, and in 2009 the FDA published their final guidelines
for testing all whole blood and component donor samples.
◦ Diagnosis- aMP-NAT or individual donor (ID-NAT) method.
◦ Identification by- IgM antibody to the WNV in serum and cerebrospinal fluid
◦ Donor criteria- The donor should be deferred from further donations for 120 days.
◦ Treatment- Once infected, there is no licensed treatment, only supportive therapy.
West Nile virus (WNV)
10. Chikungunya Virus (CHIKV)
◦ single-stranded RNA virus of the family Togaviridae
◦ Prevalence- common in India and Africa.
◦ Transmission- the Aedes family
◦ Symptoms - high fever, severe joint pain, headache, muscle pain, rash, and leukopenia.
◦ Meningoencephalitis has been described during an outbreak on Reunion Island in 2005 to
2007
◦ Treatment/ Prevention- No medication for treatment and no vaccine for prevention.
◦ Theoretically, CHIKV could be spread through transfusion, but there have been no
reported cases of CHIKV transmission through transfusion even during outbreaks.
11. Zika
◦ RNA virus and spread by the bite of an infected Aedes aegypti and A. albopictus
◦ Prevalence- Southeast Asia, Tropical Africa
◦ Transmission- via blood transfusion, from mother to fetus, and by sexual intercourse
◦ Symptoms- fever, rash, headache, joint and muscle pain, and redness of eyes.
◦ Clinical imp.- ZIKV has been associated with severe neurological complications including
increased rates of microcephaly and fetal brain anomalies during pregnancy and Guillain-Barre
syndrome.
◦ Donor criteria- FDA recommends- who have been infected with Zika not donate blood for 4
weeks. This includes those who have demonstrated symptoms or had sexual contact with people
who have traveled to countries associated with transmission.
12. Zika
◦ Diagnosis- The Cobas Zika ID-NAT
◦ Prevention- Currently, there is no vaccine for Zika.
◦ Current trends- The FDA has established ZIKV as a transfusion transmitted infection.
◦ In August of 2016, the FDA released an updated guidance for the industry requiring
testing of all donations with an individual donor nucleic acid test for ZIKV
13. EBOLA
◦ The virus was first described in 1976 near the Ebola River in the Congo.
◦ Prevalence- Central and western Africa
◦ Transmission- via exposure to blood or body fluids, contaminated needles, and
infected primates.
◦ Incubation period- 2 to 21 days.
◦ Symptoms- fever, headache, muscle and abdominal pain, fatigue, diarrhea, vomiting,
and unexplained hemorrhaging.
◦ Prevention- no FDA approved vaccine to prevent Ebola.
14. EBOLA
◦ Donor criteria- FDA recommends an indefinite deferral for a donor with disease as
well as an 8-week deferral from the date of his departure from an area with
widespread transmission of Ebola virus
◦ Current trends- The CDC has characterized Ebola as a Category A bioterrorism
agent/disease- an outbreak occurred in West Africa with nearly 29,000 suspected cases
and 11,325 related deaths.
15. Coronavirus
◦ Symptoms- common cold to severe acute respiratory syndrome (SARS-CoV)
◦ Incubation period- 1 to 14 days
◦ COVID 19 outbreak- SARS-CoV-2
◦ Infectivity by viral RNA in plasma
◦ Donor criteria- donor deferral for 28 days from complete recovery from disease or
travel/contact history & 14 days from COVID vaccination
16. Cytomegalovirus
◦ member of the herpesvirus group
◦ Once an individual is exposed, CMV can remain latent in the tissues and leukocytes for years,
with reactivation occurring from a severe immune system impairment
◦ Those at the highest risk of a CMV infection are fetuses and immunocompromised individuals
receiving allogeneic marrow transplants or solid organ transplants.
◦ The neonate may be exposed at the time of delivery, through breastfeeding, or through contact
with seropositive individuals.
◦ Approximately 1% of all newborns are infected with CMV, but most are asymptomatic at birth
17. Cytomegalovirus
◦ Transmission- person to person through contact with infected body fluids, which may include
urine, semen, saliva, blood, cervical secretions, and breast milk.
◦ CMV is the most frequently transmitted virus from mother to fetus.
◦ Detection- Antibodies formed to CMV last a lifetime and can be detected by ELISA
◦ Treatment- Currently, no treatment for a healthy individual.
Infants are being evaluated using antiviral drug therapy
Ganciclovir is being used for patients with depressed immunity.
◦ Prevention- Blood components are not universally screened for CMV because of the generally
benign course of this disease and the high percentage of virus carriers.
◦ To prevent CMV transmission, LD blood or blood from seronegative donors may be used.
18. Epstein-Barr Virus
◦ 95% of the adult population in the United States have been exposed to the virus by the
age of 40 years
◦ Maintain an asymptomatic latent infection in B lymphocytes for life.
◦ Infections occurring in infants or young children are usually asymptomatic.
◦ In adolescence and young adulthood, EBV causes infectious mononucleosis
◦ Reactivation usually occurs only in immunocompromised individuals
◦ Transmission- EBV has been called the “kissing disease” because the virus usually
replicates in the cells of the oropharynx, possibly in infected B cells. The virus is shed in
the saliva and is most frequently associated with infectious mononucleosis.
19. Parvovirus B19
◦ Causes a common childhood illness called “fifth disease”
◦ Transmission- respiratory secretions.
Pathogenesis-
◦ B19 parvovirus enters RBCs via the P antigen and replicates in the erythroid progenitor
cells. The cytotoxicity of erythroid precursors can lead to serious illness in individuals with
chronic hemolytic anemia, such as sickle cell disease and thalassemia
◦ Hydrops fetalis and fetal death can occur when the virus is transmitted during pregnancy.
◦ The viremic stage occurs shortly after infection. A donor would be asymptomatic but
capable of transmitting the virus during this period
20. Parvovirus B19
◦ Symptoms- Fifth disease presents with a mild rash described as “slapped cheek” when
occurring on the face and a lacy red rash when occurring on the trunk and limbs
Current trends-
◦ B19 has been implicated in several recent studies, with transmission through factor
concentrates, mainly an antithrombin III concentrate
◦ Has led some manufacturers and regulatory authorities to require B19 DNA
qualification testing of plasma
22. Bacteria
PREVELANCE-
◦ According to the CDC, Yersinia enterocolitica is the most common isolate found in
RBC units, followed by the Pseudomonas species. These two account for more than
80% of all bacterial infections transmitted by RBCs.
◦ Staphylococcus epidermidis or Staphylococcus aureus- most common bacterial
contaminants of blood.
◦ Propionibacterium acnes, a common isolate of human skin, was the most common
bacterial contaminant in RBCs. Slow growing anaerobic bacteria that can go
unrecognized if tested in aerobic conditions or by using short-term bacterial cultural
methods.
23. ◦ Because the bacteria in the unit consume the oxygen, the cells may lyse, resulting in
discoloration in the unit as compared with the segments that remain normal in color. It is better
to test the component itself and not the segments, as they may be negative
CURRENT TRENDS-
◦ Bacterial screening of platelets was implemented in the United States from 2003 to 2004
◦ The FDA has approved a psoralen/UV irradiation–based pathogen reduction method for use on
apheresis platelets.
◦ The 31st edition of the AABB Standards states that “the blood bank or transfusion service shall
have methods to detect bacteria or use pathogen reduction technology in all platelet components
24. PREVENTION-
◦ Phlebotomy diversion consists of collecting the first 20 to 30 mL of blood in a
separate container
◦ Water baths used in a blood bank can have high bacterial counts unless disinfected
frequently
TREATMENT- IV antibiotics and symptomatic management
26. Transfusion-Associated Parasites
◦ Most common- Babesia microti, Trypanosoma cruzi, and malaria (Plasmodium species).
◦ Several additional parasites have been identified in association with transfusion associated
Disease including Leishmania species, other Trypanosoma species, Toxoplasma gondii, and
the microfilarial parasites.
◦ Involve patients who are severely immunocompromised
◦ Donor criteria- October 2003, the AABB put forth a recommendation to blood collection
facilities that all individuals who had been in Iraq should be deferred for 1 year from the
last date of departure. This was done after cases of leishmaniasis were reported in
personnel stationed in Iraq.
27. Babesia microti
◦ Babesiosis, a zoonotic disease, is usually transmitted by the bite of an infected deer tick.
◦ Babesia infects the RBCs, so, infection may also be acquired by blood transfusion and
solid organ transplant.
◦ Symptoms- usually develop a malaria-type illness characterized by fever, chills, lethargy,
and hemolytic anemia.
◦ Incubation period- 1 to 8 weeks after transfusion
28. Babesia microti
DONATION CRITERIA-
◦ B. microti can survive in refrigerated, uncoagulated blood for 21 to 35 days. Infected
persons who donate blood during the asymptomatic period pose the greatest risk to the
blood supply
◦ Currently there is no licensed screening test for blood donors. IND protocols for antibody
and DNA testing are being used by several blood centers.
TREATMENT-
◦ no specific drug of choice, but quinine and clindamycin are very effective
◦ atovaquone and azithromycin can be as effective in patients without a life-threatening illness
29. T. cruzi (Chagas Disease)
◦ The infection is generally mild, but it persists, without symptoms, throughout the
infected individual’s life and can be transmitted through blood transfusions.
◦ Symptoms- anemia, weakness, chills, intermittent fever, edema, lymphadenopathy,
myocarditis, and gastrointestinal symptoms. Death may occur within a few weeks or
months after initial infection.
◦ Blood transmission- Following the acute phase, the disease may enter a latent phase,
which can last up to 40 years. During this phase, the patient is usually asymptomatic
but has parasites circulating in the bloodstream.
30. Chagas disease
◦ Transmission- congenitally, transplacentally, or through solid organ transplantation
◦ In 2007, some donor centers began testing, and in 2010 the FDA released their final
recommendations for donor screening by ELISA
◦ Donor criteria- Repeat reactive donors must be deferred indefinitely and the products
quarantined and destroyed.
◦ Diagnosis- No approved confirmatory tests are available.
32. Creutzfeldt-Jakob Disease
◦ one of the transmissible spongiform encephalopathies
◦ Blood transmission- Prion particles have been found in lymphoreticular tissues,
including the tonsils, spleen, and lymph nodes. As blood is intimately involved with
the lymphoreticular system, concerns arose regarding the ability of vCJD individuals
to transmit the prion to recipients of blood or blood products
◦ Currently, there is no reliable diagnostic test that can detect asymptomatic individuals.
Therefore, donors are deferred indefinitely.
33. Relevance of emergent pathogens in Transfusion practice
Examples are
◦ Human B19 parvovirus (B19V), which selectively infects erythrocyte progenitor cells,
leading to red cell aplasia, aplastic crisis or even generalized pancytopenia in patients
with immune compromise or with diseases that result in increased erythropoiesis.
◦ Some viruses, including the haemorrhagic fever viruses and dengue virus may cause
bleeding disorders, capillary leakage or platelet deficiencies.
◦ Parasites such as Babesia and Plasmodium spp. can lead to haemolytic disorders.
37. Conclusion
◦ The risks of collecting a viraemic blood donation have been calculated for specific
outbreaks such as of CHIKV, DENV and WNV.
◦ Those responsible for the safety of the blood supply are uneasy with the increasing
burden of testing and point out that this incremental approach to the maintenance of
safety is neither sustainable nor economically realistic.
◦ Many hope for a generic solution to the problem in the form of an effective and
accessible pathogen reduction technology for all blood components, but it is unclear
whether such an approach can stand alone, or whether it can only supplement other
interventions.
38. References
◦ DGHS. Tranfusion Medicine Technical Manual 3rd edition
◦ AABB Technical manual 18th edition
◦ Harmening DM. Modern Blood Banking & Transfusion Practices 7th edition
◦ Dodd R. Y. (2012). Emerging pathogens and their implications for the blood supply and transfusion transmitted
infections. British journal of haematology, 159(2), 135–142. https://doi.org/10.1111/bjh.12031
