Notes on 3. BACTERIAL VECTOR BORNE DISEASE.pptx

This ppt contains detailed notes on Bacterial vector borne diseases

1. BACTERIAL VBDS PLAGUE RELAPSING/TYPHUS FEVERS

2. PLAGUE

3. Definition Epidemiology Mode of transmission/Life cycle Predisposing factors & causes Sign/Symptoms & Complications Management Prevention and control 3 Objectives

4. Definition: Is a highly infectious bacterial disease transmitted by flea which lives on rodents. Until June 2007, plague was one of the three epidemic diseases specifically reportable to the World Health Organization (the other two being cholera and yellow fever Definition of Plague 4

5. Occurs in outbreaks with high case fatality rate of about 60% if not adequately managed. Rare but spreads rapidly! Its endemic in wild rodents living especially in the highlands. Used to cause a lot of epidemics in the middle ages. Africa is one of the few remaining foci for plague. Countries affected include: Kenya, DRC, Libya, Madagascar, Namibia, Senegal, S.A, Tz , Uganda, Mozambique, Lesotho, Mauritania and parts of Egypt. 5 Epidemiology

6. 8/14/2019 6

7. Flea bites . Bite of an infected flea. When plague infected rodents die, hungry fleas seek other sources of blood. People/animals(Dogs and cats)who go where rodents have recently died from plague are at risk of being infected from flea bites. Contact with contaminated fluid or tissue . E.g ; W hen handling tissue or body fluids of a plague-infected animal like for hunters Infectious droplets . cough droplets from an infected person if breathed in by another person can cause pneumonic plague. Life cycle & Mode of transmission 7

8. Transmission of Yersinia . pestis to an uninfected individual is possible by any of the following means depending on the type of Plague. Droplet contact  – coughing or sneezing on another person Direct physical contact  – touching an infected person, including sexual contact Indirect contact  – usually by touching soil contamination or a contaminated surface Airborne transmission  – if the microorganism can remain in the air for long periods Fecal-oral transmission  – usually from contaminated food or water sources Vector borne transmission  – carried by insects or other animals. 9

9. Caused by a Gram Negative bacilli bacteria called Yersinia pestis . Risk Factors Close contact with case Contact with infected animal Living or recent travel in endemic area Peridomestic animals running loose I.e stray dogs, cats Residing in crowded conditions Cool, wet weather Exposure to a known intentional release ( Bioterrosim ) Causes & Risk factors 10

10. Plague symptoms depend on how the patient was exposed to the plague bacteria. Plague can take different clinical forms, but the most common types of plague are: Clinical features of plague 11

11. 1. Bubonic plague: Patients develop sudden onset of fever, headache, chills, and weakness and one or more swollen, tender and painful lymph nodes (called buboes). This form usually results from the bite of an infected flea. The bacteria multiply in the lymph node closest to where the bacteria entered the human body. If the patient is not treated with the appropriate antibiotics, the bacteria can spread to other parts of the body. Signs & Symptoms 12

12. 2. Septicemic plague: Patients develop fever, chills, extreme weakness, abdominal pain, shock, and possibly bleeding into the skin and other organs. Skin and other tissues may turn black and die, especially on fingers, toes, and the nose. Septicemic plague can occur as the first symptom of plague, or may develop from untreated bubonic plague. This form results from bites of infected fleas or from handling an infected animal. 13

13. 3. Pneumonic plague: Patients develop fever, headache, weakness, and a rapidly developing pneumonia with shortness of breath, chest pain, cough, and sometimes bloody or watery mucous . Pneumonic plague may develop from inhaling infectious droplets or may develop from untreated bubonic or septicemic plague after the bacteria spread to the lungs. It is the most serious form of the disease and is the only form of plague that can be spread from person to person (by infectious droplets) & may cause respiratory failure and shock. 14

14. Sputum microscopy: shows large number of bacilli Microscopy of Pus from lymph nodes for culture and sensitivity. Full blood count Chest x-ray D iagnosis

15. Sensitive to most antibiotics except penicillin. Cephalosporins and macrolides are sub-optimal (less efficient) and should not be used. Give streptomycin IM bd or gentamycin IV/IM. Tetracycline, Chloramphenicol , doxycycline , co- tromoxazole can all also be used. Administer antibiotics for 7-10 days. Management

16. Administer medications, I.V. fluids, and oxygen as ordered and needed . Use standard precautions. Provide adequate nutrition Maintain a patent airway and adequate oxygenation. Apply warm, moist compresses to buboes. Provide meticulous skin care. Prevent further injury to necrotic tissue areas. Institute seizure precautions. Report suspected plague cases to local public health department. Nursing interventions

17. Reduce rodent habitat around homes, work places, and recreational areas, use rodent proofs, Encourage people to use rat poisons to kill rats. Wearing of gloves while handling or skinning potentially infected animals to prevent contact between the skin & the plague bacteria. Use repellent for fleas especially while outdoors i.e. camping and hiking. Keep fleas off of your pets by applying flea control products. Do not allow dogs or cats that roam free in endemic areas to sleep on your bed. Prevention and control 19

18. Early diagnosis is most important. Quarantine the area with plague (isolated from all neighboring areas.) for at least 10 days. Kill fleas using insecticides. Vaccination during an epidemic not effective. Chemoprophylaxis of all contacts: Doxcycline or cotrimozaxole if there is no pneumonic plague. 20 Don’t refer suspected Plague patients , just notify health authorities.

19. RELAPSING/TYPHUS FEVERS

20. DEFINITION A group of acute bacterial infections caused by spirochetes of the genus Borrelia characterized by recurrent cycles of febrile episodes.

21. EPIDEMIOLOGY There are two epidemiological forms: Louse borne relapsing fever Tick borne relapsing fever Louse borne relapsing fever is transmitted : ONLY between humans, by the head louse ( Pediculus capitis ) and MOSTLY the body louse ( Pediculus corporis ). It is endemic in Ethiopia, the Sudan, and Rwanda. It is a disease of poverty, overcrowding, poor personal hygiene, and infestation with lice.

22. Tick borne relapsing fever is a zoonosis, W ild rodents. (when ticks feed on infected wild rodents, they get infected). Several species of soft bodied ticks, genus ; Ornithodoros moubata , transmit tick borne relapsing fever. Ticks remain infected for life, and can transmit the infection to their offspring. Disease has been reported in Tanzania, Uganda and Rwanda .

23. Louse borne : Portal of entry, infected lice crushed near the bite wound. Louse does not transfer the spirochetes to it’s offsprings . Tick Borne : Tick sucks blood of an infected person, spirochetes multiply in the tick’s body, in a week, they are in the salivary glands of the tick and transmitted then to a new host. Ticks can survive 10 years without a meal! Spirochettes can be passed to tick’s offsprings . In humans, spirochettes can pass from pregnant mother to foetus .

24. ETIOLOGY A single organism, Borrelia recurrentis , is the cause of louse borne relapsing fever. Several different Borrelia species cause tick borne relapsing fever.

25. Spirochettes get into blood stream, circulate in great numbers during febrile periods. They also settle in the liver, spleen, bone-marrow and CNS during periods of remissions. Incubation period 2-18 days. PATHOGENESIS

26. CLINICAL FEATURES Abrupt onset of fever, 39 o C- 40 o C. The following are the dominant clinical features:

27. SYMPTOMS Fever Headaches Arthralgia / myalgia Dry cough Epistaxis /gum bleeding SIGNS Tachycardia Hepatomegaly Splenomegaly Petechiae Sub- conjunctival bleeding Jaundice Confusion/ Meningism CLINICAL FEATURES CONT’D

28. COMPLICATION S Congestive heart failure Jaundice Bleeding diathesis Jarish - Herxheimer reaction: The first dose of appropriate antibiotic causes rapid death of spirochettes leading to increased toxins in circulation . Reaction is characterised by rapid breathing, chills and a fall in blood pressure. Patients must be nursed flat, given adequate fluids and confined to bed for atleast 24 hours.

29. MANAGEMENT Aims of Management: Clinical cure Prevention of relapse Prevention/treatment of complications Antibiotic treatment: A number of antibiotics are effective: Penicillin Tetracycline Chloramphenicol Erythromycin Penicillins and erythromycin drug of choice for expectant mothers and children under 8 years.

30. Treat dehydration : Monitor blood pressure to detect hypovolemia Observe patient for signs of dehydration IV fluids for hypotension, Fever control: Tepid sponging, fanning, cooling blankets, anti- pyretics Rest : Balance between activity and rest Nutrition : Any infection interferes with feeding. Nursing management

31. Diuretics For pulmonary edema if it occurs as a complication. Prevention and control Better housing, Reliable water supply. Good personal hygiene. Insecticides like Gammatox plus for killing ticks. Nursing management Cont’d

32. Tick-borne relapsing fever Improved housing conditions Application of plaster (sand and cement) onto cracked walls. Use of corrugated-iron sheets for roofing. Use of insecticides i.e Gammexane ( Gammatox plus) Reduce exposure to the infection; use of beds for sleeping. Louse-borne relapsing fever Improved personal hygiene and use of insecticides Frequent washing and changing of clothes. Boiling clothes and drying them in the sun will kill the lice and eggs thus controlling the vector population. Routine blood smears in all patient presenting with fever. Prevention and control 34

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