COMMUNICABLE DISEASESTB, Leprosy, Chicken pox, Malaria

TUBERCULOSIS

DEFINITION: Tuberculosis, MTB, or TB (short

for tubercle bacillus) is a common, and in many cases lethal, infectious disease caused by various strains of mycobacterium, usually mycobacterium tuberculosis.

Tuberculosis usually attacks the lungs but can also affect other parts of the body. It is spread through the air when people who have an active MTB infection cough, sneeze, or otherwise transmit their saliva through the air

ETIOLOGY:

TB properly refers only to disease caused by Mycobacterium tuberculosis. Similar disease occasionally results from the closely related mycobacteria, M. bovis, M. africanum, and M. microti.

SIGNS AND SYMPTOMS

A bad cough that lasts 3 weeks or longer

Weight loss Coughing up blood or mucus Weakness or fatigue Fever and chills Night sweats

Mode of Transmission Transmission can only occur from people

with active—not latent—TB. The probability of transmission from one

person to another depends upon the number of infectious droplets expelled by a carrier, the effectiveness of ventilation, the duration of exposure, and the virulence of the M. tuberculosis strain.

The chain of transmission can be broken by isolating people with active disease and starting effective anti-tuberculosis therapy.

After two weeks of such treatment, people with non-resistant active TB generally cease to be contagious. If someone does become infected, then it will take three to four weeks before the newly infected person can transmit the disease to others

. According to The Foundation for Better Health Care, people have a 50 percent chance of becoming infected if they spend eight hours a day for six months, or 24 hours a day for two months with a person with active tuberculosis.

METHODS OF CONTROLIsolation

Immediate isolation of people who have confirmed or suspected cases of tuberculosis can help stop the spread of the disease.

Patients do not need to be kept isolated for longer than two weeks.

Isolation should last until the patient responds to treatment and is not coughing

Respiratory ProtectionThis type of protection should be worn by a healthcare worker who enters a tuberculosis patient's room. This will protect them from contracting tuberculosis.

The respirator should be a N-95 disposable particulate respirator (PR) that filters inhaled air. The respirator should be certified by the National Institute for Occupational Safety and Health (NIOSH).

A surgical mask is not adequate protection to protect someone from contracting tuberculosis.

Training Educating healthcare workers, and

anyone that might come into contact with a tuberculosis patient, is the first step in helping to prevent the spread of tuberculosis.

They should know the symptoms of tuberculosis infection, how it is spread, what the difference is between infection and disease, how it is diagnosed, how to prevent spread, and treatment for tuberculosis infection and active disease.

Ventilation One method of ventilation is dilution

and removal of contaminants in the air. An exhaust system should vent air

outside the building. Air should flow into a tuberculosis patient's room from the areas nearby, creating a low or negative pressure in the patient's room.

In hospitals that use recirculated air, HEPA filters should be installed the ventilation system. The filters remove most of the tuberculosis contaminants in the air.

UV Lamps

There are two types of UV lamps, wall-mounted or ceiling-mounted.

UV lamps disinfect the air supply in the ventilation system and inside a room. They should be left on 24 hours a day.

PROGRAM AND PREVENTION

The six components of the Stop TB Strategy are:

1. Pursue high-quality DOTS expansion and enhancement. 

Making high-quality services widely available and accessible to all those who need them, including the poorest and most vulnerable, requires DOTS expansion to even the remotest areas.

2. Addressing TB/HIV, MDR-TB and the needs of poor and vulnerable populations. 

Addressing TB/HIV, MDR-TB and the needs of poor and vulnerable populations requires much greater action and input than DOTS implementation and is essential to achieving the targets set for 2015, including the United Nations Millennium Development Goal relating to TB (Goal 6; Target 8).

3. Contribute to health system strengthening based on primary health care. 

National TB control programmes must contribute to overall strategies to advance financing, planning, management, information and supply systems and innovative service delivery scale-up.

4. Engage all care providers. TB patients seek care from a wide

array of public, private, corporate and voluntary health-care providers. To be able to reach all patients and ensure that they receive high-quality care, all types of health-care providers need to be engaged.

5. Empower people with TB, and communities through partnership.

Community TB care projects have shown how people and communities can undertake some essential TB control tasks. These networks can mobilize civil societies and also ensure political support and long-term sustainability for TB control programmes.

6. Enable and promote research. While current tools can control

TB, improved practices and elimination will depend on new diagnostics, drugs and vaccines.

Prevention and ControlThe three priority strategies for TB

prevention and control programs are: Identifying and treating individuals who have

active TB. Finding and screening individuals who have

had contact with TB patients to determine whether they are infected with M. tuberculosis or have active TB, and providing appropriate treatment.

Screening populations at high risk for TB infection and the development of TB disease to detect infected persons and provide therapy to prevent progression to active TB.

LEPROSY

DEFINITION AND ETIOLOGY Leprosy is a disease caused by the

bacteria mycobacterium laprae, which causes damage to the skin and the peripheral nervous system.

The disease develops slowly (from six months to 40 years!) and results in skin lesions and deformities, most often affecting the cooler places on the body (for example, eyes, nose, earlobes, hands, feet, and testicles).

The skin lesions and deformities can be very disfiguring and are the reason that infected individuals historically were considered outcasts in many cultures.

Although human-to-human transmission is the primary source of infection, three other species can carry and (rarely) transfer M. leprae to humans: chimpanzees, mangabey monkeys, and nine-banded armadillos. The disease is termed a chronic granulomatous disease, similar to tuberculosis, because it produces inflammatory nodules (granulomas) in the skin and nerves over time.

SIGNS AND SYMPTOMS

Skin stiffness and dryness Loss of fingers and toes Eye problems, which leads to

blindness Severe pain Muscle weakness, especially in the

hands and feet Enlarged nerves, especially those

around the elbow (ulnar nerve) and knee (peroneal nerve).

MODE OF TRANSMISSION

Leprosy results from exposure of a person to a case of leprosy,

Casual contact does not cause leprosy. This contact may be direct (e.g. skin to skin) or indirect (e.g. contact with soil, and fomites such as contaminated clothes and linen).

Leprosy has a long incubation period, an average of about three to five years.

The nose is a major portal of exit of organisms of a person affected by leprosy

Some cases of leprosy harbor millions of Mycobacterium leprae in their nasal mucosa which are discharged when they sneeze or blow the nose. The bacilli can also exit through ulcerated or broken skin of bacteriologically positive cases of leprosy.

METHODS OF CONTROL

RehabilitationRehabilitation is therefore an

integral part of leprosy control. It must begin as soon as the disease is diagnosed. The cheapest and surest rehabilitation is to prevent physical deformities and social and vocational disruption by early diagnosis and adequate treatment.

Socio–economic considerations in the control of leprosy

Preventing contact with infectious cases is an accepted method of controlling the spread of any communicable disease. It is difficult to envisage effective leprosy control without a significant improvement in the socio–economic conditions of the affected communities. The economic and social problems of the patient and his family should be identified and met.

PROGRAM FOR PREVENTIONPrevention of Leprosy for Household Contacts

People who live in the same household as a person with leprosy (household contacts) will need to be examined by a physician. These examinations should be repeated annually for five years. It is important to note that the degree of natural immunity is high, and there is often no need for preventative medicine.

 Tests and Vaccines for the Prevention of Leprosy Although there is currently no vaccine

available for the prevention of leprosy, researchers are actively working on developing one.

 

PREVENTION AND CONTROL1. Detection of cases of leprosy and tracing the

contacts especially children of the patient's house.

2. Prevention of contact between the patient and other normal persons, especially children.

3. Preventive treatment (chemoprophylaxis) with daps one.

4. Selective isolation or hospitalization of the patient showing acute reactions or complications.

5. Treatment of infected patients with daps one.6. Rehabilitation of the patient with suitable work.

Social and psychological rehabilitation is also necessary.

MALARIA

DEFINITION AND ETIMOLOGY Malaria may be characterized by cycles

of chills, fever, and sweating. It may be caused by a protozoan of the

genus Plasmodium in red blood cells, which is transmitted to humans by the bite of an infected female anopheles mosquito.

Falciparum malaria is not only more prevalent than vivax malaria, but it is also causes the highest mortality. Malaria is also known as ague, jungle fever, marsh or swamp fever, and paludism.

Chills Fever Sweats Headache Vomiting Diarrhea

Anaemia Coughing Muscle aches Watery diarrhoea Yellowing of the

skin Yellowing of the

eyes

SIGNS AND SYMPTOMS

MODE OF TRANSMISSION

1.Blood transfusion (Transfusion malaria)

Most infections occur in cases of transfusion of blood stored for less than 5 days and it is rare in transfusions of blood stored for more than 2 weeks. Frozen plasma is not known to transmit malaria. The clinical features of transfusion malaria occur earlier and any patient who has received a transfusion three months prior to the febrile illness should be suspected to have malaria.

2. Mother to the growing fetus (Congenital malaria)Intrauterine transmission of infection from mother to child is well documented. Placenta becomes heavily infested with the parasites. Congenital malaria is more common in first pregnancy, among non – immune populations.

3. Needle stick injuryAccidental transmission can occur among drug addicts who share syringes and needles.

METHODS OF CONTROLVector control

Before DDT, malaria was successfully eradicated or controlled also in several tropical areas by removing or poisoning the breeding grounds of the mosquitoes or the aquatic habitats of the larva stages, for example by filling or applying oil to places with standing water.

Prophylactic drugsSeveral drugs, most of which are also used

for treatment of malaria, can be taken preventively. Generally, these drugs are taken daily or weekly, at a lower dose than would be used for treatment of a person who had actually contracted the disease.

Use of prophylactic drugs is seldom practical for full-time residents of malaria-endemic areas, and their use is usually restricted to short-term visitors and travelers to malarial regions. This is due to the cost of purchasing the drugs, negative side effects from long-term use, and because some effective anti-malarial drugs are difficult to obtain outside of wealthy nations.

Indoor residual sprayingIndoor residual spraying (IRS) is

the practice of spraying insecticides on the interior walls of homes in malaria affected areas. After feeding, many mosquito species rest on a nearby surface while digesting the blood meal, so if the walls of dwellings have been coated with insecticides, the resting mosquitoes will be killed before they can bite another victim, transferring the malaria parasite.

Mosquito nets and bedclothesMosquito nets help keep mosquitoes

away from people, and thus greatly reduce the infection and transmission of malaria. The nets are not a perfect barrier, so they are often treated with an insecticide designed to kill the mosquito before it has time to search for a way past the net.

VaccinationVaccines for malaria are under

development, with no completely effective vaccine yet available. Presently, there is a huge variety of vaccine candidates on the table.

PROGRAM AND PREVENTIONAvoid mosquito bites Mosquitoes bite particularly at twilight

and at night, so you should take most precautions during this time.

Sleep in rooms that are properly screened with gauze over the windows and doors. There should be no holes in the gauze and no unscreened entry points to the room. Air-conditioned rooms are good, too.

Spray the room with an insecticide before entering to kill any mosquitoes that have got inside during the day.

Use mosquito repellent cream Mosquito repellent containing diethyl

toluamide (DEET) is recommended as the most effective form of bite-preventive treatment.

It has an excellent safety profile in adults, children and pregnant women and has been used in over 8 billion doses in the last 50 years.

There will always be people who dislike DEET, and for them there are other products – such as non-DEET Jungle Formual, Bayrepel or Mosiguard (made from eucalyptus oil).

Insecticide-treated mosquito nets When sleeping outdoors or in an

unscreened room, have an insecticide-treated mosquito net around your bed. This significantly reduces the risk of bites.

The net should be small-meshed, with no holes, and tucked in under the bottom sheet.

During the day, it should be rolled up, so mosquitoes and other insects can't get inside while it's not in use.

Take your own net with you. You can't always expect to find an impregnated net at your destination.

Preventive medicines Taking medicines to prevent malaria is

essential, if you're visiting an area where malaria is prevalent.

The problem can be choosing the most appropriate antimalarial for the country you're visiting. You also need to take into account your individual circumstances.

Because resistance to chloroquine and other drugs is spreading, preventive (prophylactic) medicines that were effective five years ago may no longer be so.

PREVENTION AND CONTROL Contact with mosquitoes can be

reduced by remaining in well-screened areas, using mosquito bed nets (preferably insecticide-treated nets), using a pyrethroid-containing flying-insect spray in living and sleeping areas during evening and nighttime hours, and wearing clothes that cover most of the body.

All travelers should use an effective mosquito repellent.

The most effective repellent against a wide range of vectors is DEET an ingredient in many commercially available insect repellents. The actual concentration of DEET varies widely among repellents. DEET formulations as high as 50% are recommended for both adults and children older than 2 months of age (see the Protection Against Mosquitoes, Ticks, and Other Insects and Arthropods section later in this chapter). DEET should be applied to the exposed parts of the skin when mosquitoes are likely to be present.

CHICKEN POX

DEFINITIONChickenpox is a common illness

among kids, particularly those under age 12. An itchy rash of spots that look like blisters can appear all over the body and be accompanied by flu-like symptoms. Symptoms usually go away without treatment, but because the infection is very contagious, an infected child should stay home and rest until the symptoms are gone.

ETYMOLOGY“Chicken pox,” which, to reiterate, has nothing to do with chickens, is a virus more precisely known as Varicella zoster, a member of the herpes family.  Chicken pox is a very common childhood disease that produces itchy bumps (“pocks” or “pox”) on the skin and can be very unpleasant for a week or two.  But while chicken pox can produce serious complications in adults (especially pregnant women), most cases resolve themselves fairly quickly and thereafter confer lifelong immunity to the disease.

SIGNS AND SYMPTOMS Spots first appear as pink/red lumps on the

face, scalp, chest, stomach and back. The spots are itchy and develop a watery

blister on top. In turn these blisters burst and form a yellow

crust. New spots keep occurring for about three to

four days while the older spots scab. Children may have a slight fever, feel

miserable and have a headache – though some children do not feel sick at all. In some children there will be sores in the mouth (which makes it hard to eat) and their vagina.

MODE OF TRANSMISSION Chicken Pox is transmitted from person to

person by droplet infection, and by droplet nuclei.

Most patients are infected by “Face to face”, (personal) contact.

The portal of entry of the virus is through the respiratory tract. Since the virus is extremely labile, it is unlikely that fomites play a significant role in its transmission. Contact infection undoubtedly plays a role when an individual with Herpes Zoster is an index case. The virus can cross the placental barrier and infect the fetus, a condition known as Congenital Varicella.

METHODS OF CONTROLVaccination Vaccination is the most reliable and

convenient method of preventing the chickenpox illness. The Centers for Disease Control and Prevention recommends that children get the first shot at 12 to 15 months of age with a second shot between the fourth and sixth year of life. Children over 13 years of age who are getting the vaccine for the first time should received the second dose at least 28 days after the first. Blood tests can be conducted to determine an individual's immunity to the varicella virus.