Understanding Transfusion - Transmitted Disease

Introduction

Blood transfusion is a standard practice in many countries around the world as a choice of treatment for several hematological or non-hematological disorders or in cases like acute blood loss or surgeries. Blood transfusion is a therapeutic life-saving medical procedure. An experienced team of healthcare providers performs it. The procedure involves the use of an intravenous line, and the donor's blood is transmitted to the patient's body. It is believed that more than 92 million people donate their blood every year. However, around 1.6 million of these donated blood units are discarded due to the presence of infectious or contagious disease-causing agents after observing the risk involved in blood transfusions like transmitting major infectious diseases such as hepatitis B virus, hepatitis C virus, human immunodeficiency virus, syphilis, cytomegalovirus, herpes simplex virus, Epstein-Barr virus, toxoplasmosis, and malaria. World Health Organization (WHO) has recommended testing the sample serologically to prevent the transmission of infectious pathogens.

What Are Transfusion-Transmitted Diseases?

Transfusion-transmitted diseases are comprised of different pathogens transmitted through blood transfusion. A wide variety of pathogens, including bacteria, viruses, prions, and parasites, can transfer from the donor to the recipient through a blood transfusion. Prevention of transfusion-transmitted infectious pathogens is key to eliminating the spread of life-threatening diseases. Attributes of transfusion-transmitted diseases persist a higher risk of the asymptomatic phase of a disorder in the donor despite the processing and storage of the blood unit. To avoid the associated problems, there is some intervention introduced to prevent transfusion-transmitted disease, like pathogen reduction technologies, which has improved the assessment and implementation of the blood transfusion process. In addition, it also limits irradiation to prevent transfusion-associated graft-vs-host disease and serological testing for cytomegalovirus. Recently this intervention has been approved for apheresis of platelets and plasma products.

Rewind to the time when the prevalence of transfusion-transmitted diseases became more frequent. To overcome the circumstances, blood-donor screening was introduced. In the 1940s screening for syphilis began, followed in 1970 by testing for hepatitis agents (HBsAg) and recognition of transmission associated with AIDS (Acquired immunodeficiency syndrome) in 1982. Data confirms that the spread of hepatitis and AIDS (Acquired immunodeficiency syndrome) was at its peak, demonstrating the higher risk of infection worldwide. The blood-safety interventions were implicated rapidly, not only for AIDS and hepatitis but all the other known potential transfusion-transmitted diseases. This also brings a transformation in the blood banking system, practicing blood transfusion procedures, and regular oversight worldwide.

Over the years, donor deferral criteria have been introduced to exclude donors with infectious disease risk factors, testing for major transfusion-transmitted diseases has been improved, and systematic techniques for surveillance and response to suspected emerging infectious diseases (EIDs) have been devised.

What Are the Possible Disorders Associated With Transfusion-Transmitted Diseases?

The transfusion-transmitted disease is associated with the transmission of infectious pathogens from the donor's blood to the recipient.

Following are the pathogens and diseases associated with them -

Bacterial Contamination of Blood and Its Products - Contamination of bacteria in the blood and its products is commonly seen in platelet transfusion, which is usually stored at room temperature. The infectious risk associated with platelet transfusion is approximately one in every 2000-3000 transfusions. Sepsis caused by blood transfusion is rare but can lead to life-threatening conditions.

• Gram-Positive Bacteria: Gram-positive bacteria are mostly present in an individual's skin, such as Staphylococcus epidermis or Staphylococcus aureus are most vulnerable to contaminating blood products. The contamination is caused by the bacteria present on the skin, which gets transferred into the collected blood by the needle.

• Gram-Negative Bacteria: Gram-negative bacteria like Acinetobacter, Klebsiella, and Escherichia coli are generally present in the body's gastrointestinal tract. This contamination occurs when these bacteria have invaded the bloodstream of the donor without showing any signs or symptoms. Most Gram-negative bacteria are resistant to antibiotic drugs.

• Anaplasmosis and Ehrlichiosis: Anaplasmosis and Ehrlichiosis are tick-borne disorders caused by the bacteria transmitted by black-legged tick Anaplasma phagocytophilum and Ehrlichia species, respectively.

• Brucellosis: Brucellosis is a disease caused by Brucella bacterial species called Brucella, which is transmitted to an affected individual through animal content such as sleep, cattle, and dogs. The individual may remain asymptomatic and transfer the disease through blood transfusion.

Parasitic Disease Associated With Blood Contamination: The spread of blood-contaminated parasitic diseases is rare. The donor's past medical and travel histories are recorded to reduce the risk of involvement in parasitic illness.

• Babesiosis: Babesiosis is caused by a microscopic parasite and involves red blood cells. Tick-borne transmission of the diseases is limited to specific regions and seasons.

• Chagas Disease: Chagas disease is caused by Trypanosoma cruzi, and it is mostly seen in Latin America in widespread poverty areas. The parasite is mostly transmitted from insects to animals and humans.

• Leishmaniasis: Leishmaniasis is a parasitic disease caused by 20 different species of leishmania parasite, which involves two major diseases named Cutaneous Leishmaniasis and Visceral Leishmaniasis. The bite of small sandflies transmits it, and it is spread worldwide.

• Malaria: Malaria is a severe and life-threatening disease caused by a certain type of mosquito that feeds on humans. Recent studies have reported that in 2020 around 241 million malaria cases were reported, and 627000 death cases were recorded. It is spread all over the world and shows symptoms like high-grade fever, chills, and flu-like illness.

Viral Disease Associated With Blood Transfusion: Viral diseases are blood-borne diseases like other bacterial and parasitic diseases transmitted through blood transfusion.

• Chikungunya Virus: Chikungunya virus (ChikV) is an arbovirus type of virus spread through a certain type of mosquito. Chikungunya is mostly seen in Africa, Asia, and Europe. Symptoms include high-grade fever, joint pain, and other flu illness symptoms.

• Dengue Fever: Dengue is a viral disease caused by one of the four related viruses transmitted by the mosquito. Over one-third of the world is living at risk of dengue transmission. Over the last two decades, dengue cases have continuously increased worldwide.

• Hepatitis A Virus: Hepatitis A is a contagious viral liver disease caused by the hepatitis A virus, which comes under picornavirus. It is transmitted through the fecal-oral route. In addition, cases of diseases caused by transfusion-transmitted are also reported.

• Hepatitis B Virus: Hepatitis B is a liver disease caused by the hepatitis B virus, a hepadnavirus with a double-strand DNA genome. It is reported that around 296 million people are affected with hepatitis B, and 820,00 deaths are registered worldwide. More than 15 % of cases turn into liver cancers.

• Hepatitis E Virus: Hepatitis E is transmitted by fecal-oral route in places with poor sanitation, which is caused by the hepatitis E virus and does not lead to chronic infection.

• Human Immunodeficiency Virus: The human immunodeficiency virus causes AIDS (acquired immunodeficiency syndrome). It is estimated that globally 38.4 million people are living with AIDS. The risk of transmission of the disease through blood transfusion is very high. Therefore donor screening is done.

• Human T-Cell Lymphotropic Virus: The Human T-cell lymphotropic virus is a human retrovirus that gets transmitted through sexual contact, breastfeeding, pregnancy, or blood transfusion. It is associated with neoplastic activities, opportunistic infections, and inflammatory syndrome.

Prion Disease Is Associated With Blood Transfusion Diseases: Prion is an aberrant version of a typically harmless protein found in the brain that causes a variety of fatal neurodegenerative diseases in humans, known as transmissible spongiform encephalopathies.

• Creutzfeldt Jakob Disease: Creutzfeldt-Jakob disease is an extremely rare neurological disease caused by a prion. It is a life-threatening condition.

Conclusion

Blood transfusion is a life-saving procedure performed in many treatment modalities. Transfusion-transmitted diseases are evolving, and awareness about the disease has helped in improving the blood banking system, handling the blood units, and blood donor screening. The prognosis of the transfusion-transmitted disease depends upon the type of disease transmitted. Therefore, it is also recommended to opt for a safe and secure source for blood transfusion.