Question

__________ is a causative agent of typhoid.
a. E. coli
b. Salmonella typhi
c. Salmonella paratyphi
d. Both B and C

Answer 1

This bacterium infects the intestines and the circulation of blood. For quite some time, typhoid fever had a fatality rate of about 15% that resulted in a major cause of morbidity and death worldwide.

Complete solution:

Option A is incorrect. Escherichia coli bacteria usually live in the intestines and are also present in some animal's intestines. Most are harmless as they help to keep the digestive tract healthy. But the consumption of unhealthy or contaminated food or drink fouled water, some of its strains can cause diarrhea.

Option B is correct. Salmonella typhi is bacteria in which infection of the gastrointestinal and the blood occurs is transmitted via the oral-fecal route. The condition is called typhoid fever.
Option C is incorrect. The bacteria S. Paratyphi A, B, and C cause a related disease that is classified under the heading of typhoid. Paratyphoid fever however is usually milder and shorter than typhoid fever in duration.

Option D is incorrect. Enteric fever is a general term typhoid and paratyphoid fevers are commonly grouped. Salmonella typhi causes typhoid, and either Salmonella paratyphi A, B, or C causes paratyphoid.

So, the correct answer is Option B.

Additional information:
Typhoid and paratyphoid are primarily transmitted via the oral-fecal route. Typically, an asymptomatic S. Typhi carrier or an individual who has recently recovered from the infection appears to excrete large quantities of organisms into the stool and contaminate food or water, either by the direct handling of food, the movement of bacteria by flies and other insects. Therefore, these diseases have great potential for spread in the tropics enteric fever appears to be more prevalent in the hot dry seasons when the concentration of bacteria rises in rivers and streams, or the rainy season when flooding distributes sewage to drinking water. In certain areas, typhoid incidence can be as high as 1,000 cases per 100,000 population per year. Typhoid in such a region is primarily a children's disease and the excretion of S stools. Typhi is the primary cause of infection before and after the infection. Salmonella typhi infections in such areas are fairly mild and self-limiting.

Note: There is a great impact of the infection in tropical areas as well as in many developing countries where sewage and water treatment systems are poor. As with S. Typhi and S. Paratyphi come from the same sources and in developing countries, the precise infection data caused by disease mortality and morbidity are incredibly misleading.