Question

List a bacterial pathogen associated with tick-borne infections, describe the disease and provide a strategy to prevent infection with the pathogen.

Answer 1

Borrelia recurrentis causes the relapsing fever The bacteria is spread by tick bite of genus Ornithodoros. The bacteria is found in all the tissues of tick. When tick bites it spreads the disease. Sometimes crushing a tick around a wound can also cause the disease. Rodents are also helpful in spreading the disease by acting as reservoir of ticks

Disease- The infection by bacteria causes recurring fever. the disease is charecterized by sudden high fever after 3-10 days of infection. During fever episodes high amount of Borrelia recurrentis can be found in blood. After 4-5 days fever is gone, Patient feels weakness (without fever) for few days. After 5-10 days another episode of fever happens with repeat of symptoms like chill, high temperature, weakness etc. There can be around 4-10 recurrences before complete relief from the disease. The latter episodes are generally of lesser severity.

Bacteria can be found in patient's spleen,blood, kidney and gastrointestinal tracts. Sometimes it can also be found in brain cells especially in patients experiencing meningitis.

Reason for Relapse-

The recurrence of fever is caused by antigenic variation by bacteria. The Borrelia recurrentis keeps changing it's antigenicity during single infection. This is the main reason behind recurrence of fever. The antibody of the patient target only one antigen at a time. The remaining bacteria with different antigenicity keep on dividing undetected and cause relapse of disease. Many different antigenic varients can be isolated from each relapse of disease frpm a single diseased person.

Prevention- The disease can be avoided by

maintenance of cleanliness

Avoiding bite by ticks by wearing full sleeve cloths

Avoiding lice- lice can also spread the disease during sucking of blood from one person to other. They play a role in making the disease epidemic.

Avoiding crowded area

Delousing by use of insecticides

Control of rodents as they serve as reservoir of ticks.

Maintenence of thourough cleanliness,