Chain of Infection:

An infection can occur if all the six components are present and removal of one link in the chain prevents infection. Below are the components:

• Causative agent. Refers to any micro-organism that is capable of causing disease these may be bacteria, viruses protozoa and fungi.

• Reservoir. Is a environment, object in or on which micro-organism can survive and sometimes multiply. Common reservoirs include; animals, humans and non-living objects.

• Portal of exit. The path by which an infectious organism leaves its reservoir. In relation to human may include; Respiratory tract, Skin, GIT, Genital, Urinary.

• Mode of transmission. Is the means by which infectious organism pass from the portal of exist to the susceptible host, common modes of transmission include contact, vector borne and vehicle transmission.

• Portal of entry. Is the path which an infectious organism goes through to ivadea susceptiblehost. The portal entry is usually similar to the portal exist.

• Susceptible host. The host which is vulnerable to infectious. Vulnerability may occur as result of weakened immune system of the host due to age, health, status, chemotherapy.

Mode of Transmission of Infection:

This is the means by which pathogens pass from the portal exit in the reservoir to the susceptible host. The three major modes include;
Contact transmission: A person is exposed to a pathogen by either touching or being close to an infected person or object. Can be further divided into:

(i) Direct contact transmission involves person 2 person transmission through touching, kissing, sexual intercourse etc. common diseases in this route may include hepatitis A and sexually transmitted diseases.

(ii) Indirect contact. Is a where pathogens are transferred via non-living objects such as towels, eating utensils, thermometers; beddings which are contaminated disease include Hepatitis B.
Droplet transmission; involves transfer of pathogens via infections droplets generated through sneezing, coughing and laug….. diseases by this route include common cold, whooping cough, measles etc.

Vector transmission. Refers 2 transmission of an infectious disease by the bite of an infected (block flies and sand flies).
Vehicle transmission; involves transfer of pathogens via a medium like H2O, air, blood fluids and invenous fluids administered to the patients. These diseases include cholera, typhoid.

Classification of Infections:

Infections may be classified into 2 depending on the source of infections i.e. community acquired and hospital acquired.
Community Acquired: Are infections acquired within the community, they also include infections incubating during time of hospital admission.
Routes of transmission:

• Fecal oral route. This can occur via contaminated food or house materials which are contaminated. Disease causing organisms include salmonella typhi, vibric cholera.

• Airborne route. Are spread by inhalation of infectious droplets after infected person coughing, sneezing, laughing, organisms include; measles virus, influenza virus etc.

• Direct in oculation. These occur when pathogens are injected into the body either due to accident, bite by infected animals / vectors air contaminated needles used on patients e.g plasmodium falciparum, guinea worm, HIV virus etc.

• Trans placental/mother to child. Where infections are transferred from mother to child during pregnancy delivery and after delivery like T-reponema palladium, HIV etc.

• Direct person to person contact. Most conditions on skin infections like ringworm, scabies etc.

• Sexual contact.

Nosocomial Infections (Hospital Acquired Infections):

Are infections acquired from a hospital, or health care facility when the patient is admitted for any other reason. The most common nosocomial infections in Uganda include; Pneumonia, septicemia, Sepsis, antibiotic associated diarrhea.

Causes of Nosocomial Infections:

The common pathogens than can cause nosocomial infections are mainly bacteria and include; S. aureus, Proteus spp, ecoli, Websiellaspp – mycobacterium tuberculosis.

Sources of Nosocomial Infections:

They can be endogenous or exogenous i.e. Endogenous infection (Originates from the patients normal flora) or Exogenous infections (originates from external sources which include;

Acutely all patients, Asymptomatic patients (people incubating on infection), Inadequate sterilized equipment’s, Hospital staff during patient care, Healthy carries).

Main routes for transmission of nosocomial infections include; Contact with infected persons, Air borne, Direct inoculation, Facial oral routs.
Factors Contributing to Nosocomial Infection: Failure to health care workers to follow injection control guidelines. Increasing number of patients with compromise immunity. Overcrowding of patients in the hospital. Prolonged stay in the hospital. Age in that a patient with adversed age and young ones like babies are more susceptible to infections. Underlying diseases such as diabetes mellitus, renel failure tend to lead to increased susceptibility. Drugs being administered like nati-cancers and steroids tend to lower body or hosts’ immunity.

Patients at Risk of Nosocomial Infection:

Patients with compromised immunity due to diseases like HIV or immune suppressive drugs. Patients with broken skin (wound). Patients undergoing surgery characterization ventilation. Women in labour and delivery. Highly old and young patients.

Consequences of Nosocomial Infection: Prolonged stay in the hospital which may result into dark. Increases the cost of medical care i.e. drugs. Infected person may become a source of infections to other patients.

Prevention of Nosocomial Infection: Protecting patients with appropriate use of prophylactic anti-microbial, nutrition and vaccination. Limiting the risk of endogenous infections by minimizing invasive procedures and promoting optimal microbial use.

Prevention of infections among the staff members. Enhancing staff patient care. Surveillance of infections i.e. identifying and controlling outbreaks. Health education of both patients and staff members. Use of appropriate a septic practices like hand washing, sterilization, disinfection. Isolation of infectious patients from other patients.

Universal Precaution / Principles of Infection Prevention and Control:

Are a set of guidelines developed by the center of disease control and prevention in order to avoid contact with potentially infective body fluids and objects such as csf, pleural fluid, blood, amniotic fluid etc. which may harber infections such as hepatitis B, Hix. They include; Hand washing, Safe waste management, Adequate protective gears, Proper sharp disposal, Proper sterilization disinfectant.
Other general measures include:

1. Hand washing. This is effective measure for preventing the spread of pathogens. There must readily accessible hand washing facilities in a hospital. For example soap most especially liquid soap for hand washing and running water and towel for drying hands immediately after washing.

2. Sterilization, this is the process intendedto kill am microorganisms and is a highest level of microbial kill that is possible, sterilizers may be heat only, steam or liquid.

3. Cleaning, infections can be prevented fromaccuring in hospital/home as well in order to reduce their chances to contract on infections, patients medical perfuse are recommended to maintain.

4. Disinfection. Disinfection uses liquid chemicals on suraces and at room temperature to kill diseases causing microorganismultras let light has also been used to disinfect the rooms of patients infected with clostridium difficult after discharges.

5. Personal protective equipment e.g. gloves, bonnets, shoes, covers, face shield, surgical mask and respirators. Many are most of those items are disposable to avid carrying infections materials from the patients to another and to avoid difficult or costly to disinfection.

6. Auti microbial surfaces, microorganisms are known to survive on non-antimicrobial in animate “touch” surface e.g. bedrails, over-the-bed trays, call buttons, bathroom hard wore etc. as a public hygienic measure in addition to regular cleaning.

7. Vaccination of health care workers.

Waste Management and Disposal:

Refer to how the different wastes in hospital and homes are segregated. The methods used for disposal of wastes from hospital and homes are almost similar.

The main difference is the type and amount involved. In medical field wastes and their disposals is of high standards due to the fear of infection spread to the handlers and public.

General Principles of Segregation, Storage and Transportation:

All health care workers should understand the risks and safety procedures for the wastes they are handling.

All the containers which are filled with wastes should labeled to help the person in charge and to control the workers. Separate containers should be available in each a medical area for proper segregation of wastes. Local storages inside or near to a medical area may be needed if wastes are not collected frequently. Do not mix hazardous and non-hazardous wastes during collection, transport and storage. Collection wastes are often taken to central storage site before treatment and disposal.

Health Care Wastes:

Is the total wastes generated in healthy facility during health care service delivery like during diagnosis, prevention and treatment of diseases.

Types of Wastes:

Wastes may be classified into two;

Hazardous health care wastes (Is a waste with potential to cause harm to both human and environment if improperly handled. Almost 20% of all health care waste is estimated to be hazardous. Examples include; Un used blood, Human tissue, Contaminated animal carcasses, Disinfectants, Drugs, Needles, Syringes, Laboratory reagents, Swabs and bandages) and

Non-hazardous flow (Are wastes that are harmless to both humans and environment. They contribute almost 80% of wastes generated in a health facility, although they are harmless, they become nuisance when not appropriately disposed off. Examples include; papers, boxes, empty tins and discarded food).

Segregation of Medical Wastes:

The responsibility of segregation of wastes lies one person who has generated the wastes.

All wastes should be segregated and disposed off in their appropriate container. Cobour coding also provides a visual indication of the potential risk posed by the wastes in that container i.e. Red – highly infectious wastes, Yellow – infectious wastes, Brown – pharmaceutical and chemical wastes, Black – general/noninfectious wastes, Yellow/ white sharp container for sharp wastes only.

Segregated wastes become easy to be carried by the workers in that if bins become full, its liner wrapped tightly and taken to incineration.

Waste Segregation Chart: