Health Hygiene & Sanitation

Lesson 35 : Prevention Of Respiratory Infections

Exanthematous Diseases

Exanthems are eruptions of skin accompanied by inflammation.

Enanthems are eruptions of the mucous membrane.

Types of Exanthems/Rashes:

• Macule- flat lesion not raised above the surface.
• Papule- small palpable lesion elevated above the surface.
• Nodule- large papule.
• Vesicles- small blisters.
• Bullae- large blisters.
• Pustules- small pus filled lesions.
• Plaque- large, palpable but flat lesions.

Classification of Exanthematous Diseases:

• Maculopapular- measles, rubella, hepatitis B, herpes, certain bacterial and fungal infections.
• Nodular- fungal diseases, leprosy, tuberculosis, hepatitis C, inflammatory bowel disease, certain drugs, etc.
• Diffuse erythematous with peeling or desquamation- scarlet fever, toxic shock syndrome, Steven Johnson syndrome, etc.
• Vesiculobullous- varicella(chicken pox), herpes virus,etc.

Petechial/purpuric- malaria, certain viral and bacterial infections

Exanthematous Diseases:

FEATURES	CHICKEN POX (Varicella)	MEASLES(Rubeola)	RUBELLA (German measles)
Agent Factors
Agent	varicella-zoster virus	RNA paramyxovirus	RNA togavirus
Source	oropharyngeal secretions, skin/ mucosal lesions of a CASE,	Case of measles, secretions of nose, throat and respiratory tract.	Cases of rubella, secretions of nose, throat, blood, and urine. Infants with congenital rubella shed virus.
Communicability	1 to 2 days before appearance of rash to 4-5 days thereafter	4 days before and 5 days after the appearance of rash.	Less communicable as no coughing, week before symptoms to week after rash appears. Infectivity is greatest when rash is erupting.
Host Factors
Age	<10 yrs, Severity increases with age.	Between 6 mon to 3 yrs in developing countries and > 5 yrs in developed countries.	Between 3 to 10 years, >15 years account for 70% cases in developed countries.
Immunity	Once infected lifelong. Infants upto 6 months are protected by maternal antibodies. Pregnancy- risk for the fetus and the new born.	Once infected lifelong. Infants upto 6 months are protected by maternal antibodies. Nutrition- severe in malnourished children.	Once infected lifelong, women of child bearing age are susceptible to rubella infection.
Environmental factors	Mostly during first 6 months of the year in India. Little evidence of seasonal trend in temperate climates. Overcrowding favours transmission.	Virus can spread in any season. In India-Jan to April. In temperate climates, it is a winter disease. Overcrowding favours transmission.	Usually occurs in a seasonal pattern i.e. in temperate zones during the late winter and spring, with epidemics every 4-9 years.
Transmission	Portal of entry-respiratory tract. Transmission by droplet infection and droplet nuclei- Face-to-face (personal contact) Contact infection when case is a herpes zoster patient. Virus can cross placental barrier hence fetus can be infected (congenital varicella)	Person to person spread occurs by droplet infection and droplet nuclei. Portal of entry is respiratory tract. Infection through conjunctiva is also likely. Recipients of measles vaccine are not contagious to others.	Portal of entry- respiratory route. Transmission by droplets from nose and throat, and droplet nuclei (aerosols). Virus can cross the placenta (vertical transmission) leading to congenital rubella.
Incubation	About 15 days	10-14 days from exposure to onset of fever or appearance of rash	About 18 days
Clinical features	mild to moderate fever, back pain, malaise for 24 hrs. In adults it may last for 2 to 3 days before the rash comes out. In children, rash is the first sign, seen on the day of fever. Distribution of rash is symmetrical. Sequentially appears on trunk, face, arms, legs. Palms and soles are usually not affected. Rash is superficial, dew drop like, advances rapidly through the stages of macule, papule, vesicle and then dried scab. Important feature -different stages of rashes can be seen at one given time as they appear in successive crops. Temperature rises with each fresh crop of rash but does not run high.	Fever, coryza, sneezing, nasal discharge, cough, redness of eyes, lacrimation and photophobia. A day or two before the appearance of rash, KOPLIK’S SPOTS appear on the buccal mucosa opposite first and second upper molars. Eruptive stage-Dusky red, macular or maculopapular rash typically beginning behind the ears and spreading rapidly to face and neck in a few hours, and extends down the body in 2 to 3 days. Rashes may become confluent with time. Rash fades in the same order of appearance leaving brownish discolouration that persists for >2 months. Post measles stage - weight loss, weakness, increased susceptibility to bacterial and viral infections, growth retardation, diarrhoea.	Majority (50 to 65%) are asymptomatic. Coryza, sore throat, and low grade fever. Lymphadenopathy-before the onset of rash and may persist for 10 to 14 days after the rash. Rash-often first indication of disease in children. First appears on face. Conjunctivitis may occur. Rash spreads rapidly to trunk and extremities and disappears from face. It disappears altogether by third day. Rash is absent in subclinical cases.
Control	No specific treatment. Only symptomatic treatment with rest, fluids and antipyretics. Notify disease to concerned authorities. Isolation of the case for about 6 days after the onset of rash. Disinfection of articles soiled by nose and throat discharges.	Isolation for 7 days after onset of rash. Immunization of contacts within 2 days of exposure Prompt immunization at the beginning of an epidemic to limit the spread.	-
Prevention	‘LIVE’ attenuated vaccine, Varicella zoster immunoglobulins within 72 hrs of exposure recommended for immune-suppressed contacts of acute cases or new born contacts.	‘LIVE’ attenuated vaccine given at 9 months of age. Human immunoglobulin within 3 to 4 days of exposure in non immunized individual. It must and should be followed by immunization with live attenuated vaccine 8 to 12 weeks later.	‘LIVE’ attenuated vaccine available as combined mumps, measles and rubella (MMR), no vaccination to infants to avoid possible interference from persisting maternal antibodies. Recipients of the vaccine must not become pregnant over next 3 months.

Congenital Rubella Syndrome: It refers to infants born with defects secondary to intrauterine infection or who manifest symptoms or signs of intrauterine infection sometime after birth. Rubella inhibits cell division, and this is probably the reason for congenital malformations and low birth weight.

Congenital rubella is a chronic infection while acquired rubella is an acute infection. The fetus remains infected throughout gestation and for months and years after birth. The gestational age at which infection occurs is the major determinant for the extent of infection and the effects on the fetus.

First trimester of pregnancy is the most disastrous time as the organs develop during this period. If the infection is serious, spontaneous abortion and still birth may occur, or the infant may develop multiple defects- the classical triad of patent ductus arteriosus, cataract and deafness. Others include glaucoma, retinopathy, microcephalus, cerebral palsy, intrauterine growth retardation, hepatosplenomegaly, mental retardation. Infection in the second week may cause deafness, those infected after 16 weeks suffer no major abnormalities.