Infections are a major cause of disease and death in children. Infections occur when there is entry, development and multiplication of an infectious agent in the body of an individual. These infectious agents (germs) include bacteria, viruses and fungi which are microscopic organisms (so small they can only be seen with the aid of a microscope). The individual often responds to defend itself. The combined effects of the infectious agent and the response of the individual are responsible for the signs and symptoms of disease.
Not every infection results in disease. There are several factors that determine whether an infection will result in disease. These factors include
1) The characteristics of the infectious agent. Some infectious agents are highly infectious eg Hepatitis B virus. Others are highly virulent such that very small numbers of the organism can cause infection egshigella which causes dysentery
2) The level of immunity of the individual- There are several levels of defence against invasion and infection by infectious agents. The skin is the first barrier to infection, thus occurring when there is an injury. Specific immunity by cells and antibodies (these are the “soldiers” in the blood that fight infection and foreign materials) is also important. Children may have congenital immunodeficiency (that is, they are born lacking the ability to fight off infections) or may lack specific immunity to certain infections because they were not immunized. Children are particularly vulnerable to infections because their immune system is relatively immature compared to adults.
The presence of other conditions such as HIV infections diabetes mellitus or a recent measles infection may also weaken the immune system such that infectious agents which ordinarily should not cause problems will result in infection
3) Nutritional state- malnourished children tend to be more vulnerable to infections
4) Prematurity- Premature babies are more prone to infections compared to babies born at term because of the immaturity of their immune system and also because they did not receive adequate antibodies from their mothers because they were born prematurely
Transmission of Infections
How do infectious agents get to children? An infectious agent may be transmitted from one person to another through various mechanisms. Transmission can be direct or indirect. Direct transmission can occur through
– Direct contact- this means there is contact of skin to skin, mucosa to mucosa, mucosa to skin, between an infected person and the susceptible person. Skin to skin contact in children can transmit such skin infections as scabies, ringworm. Sexually transmitted infections can occur in sexually active adolescents.
– Droplet infection. During coughing, sneezing, talking and spitting, secretions and saliva are carried from one person to another as small droplets. These droplets can land on the mucosa of the eye, the skin and can be inhaled. These droplets may carry infectious agents and may result in disease like tuberculosis,respiratory tract infections, whooping cough
– Contact with soil. The soil harbours many infectious agents. For example the spores of the tetanus-causing organism are found in the soil and when soil contaminates injuries it can lead to tetanus.
– Direct inoculation into the skin or mucosa can occur for example a bite by a rabid dog can cause rabies, use of contaminated needles/sharps like razor blade used for scarifications can lead to HIV and hepatitis B infections.
– Transp some infections can cross from a mother to her unborn baby through the placenta eg syphilis, HIV
Indirect transmission of infection can also occur as in
– Vehicle borne- the infectious agent can be carried through such vehicles as food, water, blood
– Vector borne- vectors are living carriers of the infectious agent. Vectors include insects such as mosquitoes, cockroaches, flies, lice, ticks. These vectors transmit infection through their bites as in mosquitoes, by regurgitation such as flies.
– Airborne- some infectious agents are found in dust eg tuberculosis. When air containing such infectious agents is inhaled it can lead to disease. Such air borne infectious are common in overcrowded homes with poor ventilation.
– Fomite borne; fomites are inanimate objects like toys, books, pencils, cups, towels. Unclean hands and fingers can easily transfer infectious agents to food and directly into the mouth, Diarrhoea) typhoid and dysentery can be transmitted through this mechanism
INFECTIONS IN CHILD CARE SETTINGS
Children often have to be cared for outside of their homes. Children may be cared for in cretches, play groups, pre-school and school. Children in these settings have increased frequency of coming in contact with infections from other children and from care givers. It has been shown that young children (less than 5 years) cared for outside the home setting have increased numbers of upper and lower respiratory infections compared to those cared for at home. Young children newly entering child care facilities are particularly at high risk of respiratory tract and enteric infections (diarrhoea). Factors that contribute to the transmission of infections in child care settings include the following
– The age and developmental stage of the child are very important factors contributing to the transmission of infection. Infants (less than 1 year old) and toddlers (12-35 months old) who are still in diapers or need assistance using a toilet present more hands on contact with care givers. These children have oral contact with the environment(putting objects in their mouths), have poor control over their secretions and excretions and they are developmentally less immune. These children also require assistance with feeding. Infants and toddlers also have frequent direct contact with each other and with the secretions of other toddlers. These characteristics and the high potential for contact create a conducive setting for the transmission of infections such as ringworm, scabies, diarrhoea
– Poor hand hygiene- when care givers and food handlers do not observe adequate hand hygiene they can spread infections like diarrhoea, typhoid by introducing the causative organisms of these diseases into food and water meant for the children.
Poor cough etiquette.- leads to spread of respiratory tract infections. While young children with tuberculosis usually do not spread the infection, this is not so with the adult care giver. An adult care giver who is infected with tuberculosis can spread the infection to the children being cared for as well as to other care givers in the facility.
Common infections in child care settings
The opportunity for spread of infectious agents that affect the gastrointestinal tract is readily provided because of the close personal contact and suboptimal hygiene of young children. These infectious agents include rotavirus, shigella, hepatitis A virus, salmonella. Contamination of the environment by faecal material is also common in child care facilities especially where there are infants and partially toilet trained toddlers. Infectious agents can easily spread in such settings through direct person to person contact and indirectly via fomites, environmental surfaces and food. The potential for environmental contamination is increased when inmates have diarrhoea.
Respiratory infections are also very common in child care facilities. Common infectious agents for respiratory infection include Haemophilusinfluenzae, Streptococcus pneumoniae, Mycobacterium tuberculosis, Neisseria meningitides. Some of the diseases caused by these agents include pneumonia, otitis media, meningitis. Although the risk of contact with blood infected with HIV, Hepatitis B and C is low it is important to prevent the transmission of blood borne infectious agents.
