INFECTIOUS DISEASES INFECTIOUS DISEASES

DOC 1 ( GROUP 3)DOC 1 ( GROUP 3)

• Rickettsiosis/rickettsioses are a group of diseases generally caused by species of Rickettsia.

• They are obligate intracellular gram-negative coccobacillary

• multiply within eukaryotic cells.

• Rickettsiosis/rickettsioses are a group of diseases generally caused by species of Rickettsia.

• They are obligate intracellular gram-negative coccobacillary

• multiply within eukaryotic cells.

INTRODUCTION

• A general characteristic - mammals and arthropods are natural hosts.

• Rickettsioses are usually transmitted to humans by arthropods.

• A general characteristic - mammals and arthropods are natural hosts.

• Rickettsioses are usually transmitted to humans by arthropods.

A.Spotted fever biogroup Rocky Mountain spotted fever

Rickettsialpox

Boutonneuse fever

B.Typhus group Louse-borne (epidemic) typhus

Brill-Zinsser disease (ie, relapsing louse-borne typhus)

Murine (endemic or flea-borne) typhus

C. Scrub typhus biogroup (Tsutsugamushi disease).

The rickettsia can be classified into three groups according to serology

Q fever Q fever It is an exception

caused by Coxiella burnetii

recently been removed from the Rickettsiales.

described here for comparison with other rickettsioses.

It is an exception

caused by Coxiella burnetii

recently been removed from the Rickettsiales.

described here for comparison with other rickettsioses.

Rickettsiae multiply within the endothelial cells of small blood vessels ,

gain access to the bloodstream after skin inoculation.

Focal areas of endothelial proliferation and perivascular mononuclear cell infiltration cause leakage of intravascular

fluid into tissue space.

Effect on all organs, i.e; skin

Systemic effects: CNS & Heart : damaging host response accompanies vasculitis.

Liver - usually affected with portal triaditis.

Vascular wall destruction consumes platelets, causing thrombocytopenia.

Multiple factors

hypoalbuminemia ; eg, renal loss, hepatic involvement.

hyponatremia ; eg, renal loss

Systemic effects: CNS & Heart : damaging host response accompanies vasculitis.

Liver - usually affected with portal triaditis.

Vascular wall destruction consumes platelets, causing thrombocytopenia.

Multiple factors

hypoalbuminemia ; eg, renal loss, hepatic involvement.

hyponatremia ; eg, renal loss

• Study carried in Eastern province ( Kibungo prison)

• Epidemic Typhus in Kibungo Prison, Eastern Province.

- Blood samples collected from 14 cases revealed Rickettsia prowazekii in 11 samples (From week 14 of 2013)

- end of week 16 The visit revealed that all suspected cases have been treated using Doxycycline.

-

• Study carried in Eastern province ( Kibungo prison)

• Epidemic Typhus in Kibungo Prison, Eastern Province.

- Blood samples collected from 14 cases revealed Rickettsia prowazekii in 11 samples (From week 14 of 2013)

- end of week 16 The visit revealed that all suspected cases have been treated using Doxycycline.

-

• Bite by- fleas, lice, mites, and ticks during feeding.

• scratching crushed arthropods or infectious feces into the skin.

• Inhaling dust or inoculating conjunctiva with infectious material.

• transfusion or organ transplantation is rare

• Bite by- fleas, lice, mites, and ticks during feeding.

• scratching crushed arthropods or infectious feces into the skin.

• Inhaling dust or inoculating conjunctiva with infectious material.

• transfusion or organ transplantation is rare

SIGNS & SYMPTOMSSIGNS & SYMPTOMS

• a small, hard, black sore on bite site• Fever reaches 40-41°C • Rash on extermities.• Skin necrosis is rare• Neurologic findings – seizures, ataxia,

paralysis

• a small, hard, black sore on bite site• Fever reaches 40-41°C • Rash on extermities.• Skin necrosis is rare• Neurologic findings – seizures, ataxia,

paralysis

• These infections are not common and usually mild they can be difficult to diagnose.

• blood test

• skin biopsy (for example a sample of skin) of the bite site.

PREVENTION

• There is no vaccine available to prevent infection.

• long sleeved protective clothing –• an insect repellent

• There is no vaccine available to prevent infection.

• long sleeved protective clothing –• an insect repellent

• Adequate antibiotic therapy initiated early in the first week of illness

• Doxycycline is the drug of choice

• Chloramphenicol may be used as an alternative

REFERENCES

• www.medterms.com• www.medscape.com

• www.medterms.com• www.medscape.com