Decades after the development of vaccines and antibiotics, infectious diseases have not disappeared as was predicted.
For the prevention and control of Infections, knowledge of its epidemiology is needed.
Definitions are critical for any type of epidemiological action e.g.
*Disease reporting,
*Measurement of mortality and morbidity
The steps lead to the calculation of the value of. x^2 for the study data
Value of the calculated x^2 is referred to the x^2 -table -where the ‘p’ value seen
Test can be applied:
a) On qualitative data
b) Random sample
c) The lowest observed frequency in all the cells is 5 or more
d) None of the observed values is zero
Advantages (over ‘SE of diff bet two means’ test):
a) Equally applicable for small samples and large samples
b) The test can be used even if there are >2 categories
Suspect case
A. A patient with acute respiratory illness (fever and at least one sign/symptom of respiratory disease (e.g., cough, shortness of breath), AND with no other etiology that fully explains the clinical presentation AND a history of travel to or residence in a country/area or territory reporting local transmission of COVID-19 disease during the 14 days prior to symptom onset.
OR
B. A patient with any acute respiratory illness AND having been in contact with a confirmed or probable COVID19 case in the last 14 days prior to onset of symptoms;
Standard Error of Difference between Two Proportions 
(blog under construction)
Chi-square test or 
(blog under construction)
Unpaired-‘t’ test (or simply, the't'-test) (blog under construction)
‘Z’ test (blog under construction)
Paired 't'-test– For Paired values (blog under construction)
Tests of significance are used for comparison between two or more groups
The difference may be just by chance OR
The may be an actual difference between the two (or more) groups and there may be a reason for that
• The vaccine against rotavirus diarrhea has been introduced recently in the National immunization schedule.
• Oral cholera vaccines are available, which gives immunity to 50-60% of those who take the vaccine, and this immunity lasts only a few months.
• Measles vaccine prevents measles. Diarrhea is a frequent complication of measles
Other vaccines help by preventing infection with vaccine preventable diseases, thereby preventing some parenteral diarrhea.
Three aspects of diarrhea control interventions are measured through indicators:
1. Indicators of Diarrhea Prevention
2. Indicators of Diarrhea Treatment
3. Indicators of ORT use
Two components of diarrhoeal diseases control
A. Short term
– Assessment and appropriate clinical management of cases
B. Long term
1. Better MCH care
2. Preventive strategies
3. Preventing outbreaks
A. Rehydration therapy,
B. Antibiotics ONLY IF indicated
C. Zinc supplementation and
D. Continued feeding
The clinical features due to various causative agents may overlap and may even be atypical
Following is a list of commonly seen clinical features associated with different agents.
Also, the general principles of diarrhea management are similar for most causative agents.
CLINICAL FEATURES: CHOLERA
• Rice-watery stool
• Marked dehydration
• Projectile vomiting
• No fever or abdominal pain
• Muscle cramps
• Hypovolemic shock
• Scanty urine
CLINICAL FEATURES: E. COLI (ETEC) DIARRHEA
