Give an account of infections transmitted via blood and blood products. How can health workers protect themselves from acquiring such infections?

Outline:
•	Blood-borne infections:
- bacteria: pseudomonas spp., yersinia 
- virus: HIV, hepatitis B
•	Precautions & preventive measures:
- general measures
- safe handling and disposal of sharps
- reduce risk of blood-skin contact.
- decontamination and waste disposal.
- management of exposed cases

Suggested Answer:

	Transfusion of blood and blood products carries a risk of transmitting blood-borne microorganisms. Infection was common in the early days of blood transfusion, when reusable collection sets were in use and blood was not routinely screened for viral agents. The patients now at greatest risk of transfusion-associated infection are either patients who have had multiple units of blood (e.g. during cardiac surgery) or those who require blood products pooled from many donors (e.g. haemophiliacs). 

	The microorganisms most commonly implicated are either bacteria or viruses. Bacteria may cause overwhelming systemic sepsis, usually within minutes to hours of the onset of transfusion. There is a high mortality rate when this occurs. Viral infection has a much longer incubation period and may only become clinically apparent months after transfusion. Bacterial infection is usually the result of contamination at the time of donation, poor storage, contaminated equipment or a combination of these. Viral infection is usually caused by the presence of viral infection in the donor. Bacteria include Citrobacter spp., Pseudomonas spp. and Yersinia enterocolitica. Viruses include hepatitis B and C viruses, human immunodeficiency virus and cytomegalovirus. A severe acute transfusion reaction resulting from infection may take the form of septicaemia. 

	Needle-stick and other sharp injuries are the most common means of transmitting hospital-acquired HIV infection and hepatitis B. These injuries are frequently the result of recapping of hypodermic syringe needles after completion of venesection, but other reasons include encounters by domestic staff with discarded needles hidden in bedlinen and pricking by sutures or scalpel blades during surgical procedures. The common site of injury is the thumb or forefinger of the non-dominant hand.

	Healthcare workers should be advised to get themselves vaccinated against hepatitis B virus. General measures to reduce the risk of exposure are washing hands before and after contact with each patient, and putting on and after removing gloves; change gloves between patients; cover existing wounds, skin lesions and all breaks in exposed skin with waterproof dressings and avoiding sharp usage wherever possible and where sharps usage is essential, exercise particular care in handling and disposal.

	Many percutaneous injuries are preventable. Implementation of the following procedures for the safe handling and disposal of sharps will reduce the risks: place all disposable sharps in sharps container after use; provide sharps containers in adequate numbers and never overfill; avoid re-sheathing needles manually; discard disposable syringes and needles wherever possible, as a single unit and removing needles from syringes only when essential. Wearing of gloves can reduce the risk of acquiring blood-borne infections and therefore healthcare workers should wear gloves when using a sharp equipment or during surgical procedures. 

	The following measures reduce risk of blood-skin contact: if a glove puncture is suspected or recognized, rescrub if possible and reglove as soon safety permits; change gloves regularly if performing, or assisting with a prolonged surgical procedure; wear protective headwear or surgical masks; ensure that all blood is cleaned from a patient’s skin at the end of an operation before patient leaves theatre and removing protective clothing including footwear when leaving the contaminated area.

	Decontamination and proper disposal of medical equipments can prevent occupational exposure to blood-borne infectious agents. Single use equipment should be used where appropriate, particularly where decontamination cannot be carried out effectively. Reusable equipment must be of a type that is readily decontaminated without damage to its structure or function. Thorough physical cleaning of instruments in warm water with detergent to remove blood and debris is essential prior to disinfection or sterilization. All waste which is contaminated with blood, tissues or other potentially infectious body fluids should be treated as ‘clinical waste’ and disposed of properly. Clothing and linen stained with blood or body fluids which is to be reused should be handled with care and placed in suitable bags for safe storage and transportation for laundering. 

	Sharps injuries should be reported to the supervising staff. Serum should be taken from the patient and the staff member. The patient’s serum is then tested for evidence of hepatitis B and C and when permission is given, for HIV infection. The staff serum is stored for comparison with a further serum specimen to demonstrate seroconversion, or for further testing if the patient’s serum is hepatitis B positive. Staff will normally require counselling regarding the risk of hepatitis and HIV infection. Transmission of hepatitis B virus occurs far more readily than HIV. If the patient is hepatitis B positive, the staff serum should be checked for antibodies to hepatitis B surface antigen. If the titre is low or absent, a booster dose of vaccine is required, along with a dose of hepatitis B immunoglobulin.