Transfusion Associated

Malaria

Dr Prakash.I

Introduction

Special consideration

Rarity

Delay in diagnosis

Treatment

Serious complications

1st reported in 1911

In non-endemic countries - incidence is low

Canada between 1994 and 1999 -3 cases , USA between1990 and 1999 -14 cases ,UK since 1996 -2 case, OtherEuropean countries-2 cases

US- <0.3 case/million transfused blood units

Uniqueness - caused by injection of asexual forms (Trophozoite)

Trophozoite-induced malaria Vs natural infection

pre- erythrocytic schizogony - absent

short incubation period

exo-erythrocytic schizogony - not seen

relapses do not occur

radical cure is possible

In donor blood

Relapsing illness : P. vivax and P. ovale

Asymptomatic parasitemia- variable anddepends on species

P. vivax and P. ovale rarely persist > 3 years

P. falciparum rarely > 1-2 years(3 mo)

P. malariae parasites for decades

Donor-exclusion criteria's aim : balance betweenrisk of malaria and excluding uninfected donors

Drawback in prevention : screening techniquesnot satisfactory

Criteria for suitable test for screening:

large-scale use design

high sensitivity and specificity

detect all 4 species of Plasmodium

Blood film microscopy

Traditional blood film microscopy –

large manpower

high technical skill

limited sensitivity

Microscopic exam (thick blood film-4 ml): Asingle parasite equivalent to ∼10,000parasites ina 450-mL unit of blood

Antibody detection test

Antibody detection: ELISA, immunofluorescenceassay (IFA)

Malaria antibody testing :95% sensitive and 99%specific

In endemic malaria: PPV for this test is high

Malaria antibody screening

do not indicate active infection

high discarding of collected blood units (as Ab may persist for several years after infection)

Residents in malaria-endemic countries: have anti-malarial Ab-serologic tests are unhelpful forscreening donors

Donors from Endemic region: immunity tomalaria→ low levels of parasites without clinicalsymptoms, undetectable levels of parasitaemia

Antigen detection test

Antigen detection by MAB (monoclonalantibody) technique :

more sensitive

practically feasible screening test

PCR and antigen detection tests - limitedavailability

Blood transfusion recipients

Nonimmune recipient - can become rapidly fatal

Young infants in malaria endemic regions-nonimmune recipients

Clinical severity different : Endemic Vs Nonendemic

Blood products

Whole-blood and RBC concentrates -mostcommon source.

Platelets, FFP, and leukocytes may infrequentlytransmit malaria.

As few as 15 parasites (one bite): can causemalaria.

Prevention

Endemic countries: specific donor questioning considering

Seasonal variation

Geographical distribution

Antigen detection by monoclonal Ab as a routine screening procedure : in endemic countries

Anti-malarials to recipients may help to prevent transmission

Prevention largely depends on careful questioning donors

FDA recommends deferring residents

Endemic areas : 3 years

Had malaria/Chemo : 3 years (after they become asymp.)

Non endemic : 1 year after return from malarious area

In EU

Endemic area : 3 yrs

Non-endemic areas donors: 4-12 months

Some countries reject these donors(NED) for 3 yearsor permanently (if resided for >6 months in theendemic area)

Evidence based

Support for Recommendations:

97% and 99% of the reported malaria cases inU.S. and foreign civilians occur within 1 and 3years, respectively, of having been in a malariousarea

AABB: Uniform donor history questions

Travelers may donate blood 6 months after returningfrom endemic areas if they have been free of symptomsand have not taken antimalarial drugs

Persons who have had malaria or who had been takingchemoprophylaxis shall be deferred from donating bloodfor 3 years after either becoming asymptomatic orstopping therapy or chemoprophylaxis

Immigrants or visitors from endemic areas may beaccepted as donors 3 years after departure if they areasymptomatic in the interim

Donations for preparing plasma, plasma components, orderivatives devoid of intact red blood cells are exemptedfrom these restrictions

Thank You