Zoonoses in West Texas. Ken Waldrup, DVM, PhD Texas Department of State Health Services

Transcription

1 Zoonoses in West Texas Ken Waldrup, DVM, PhD Texas Department of State Health Services

2 Notifiable Zoonotic Diseases Arboviruses* Anthrax Brucellosis Bovine Tuberculosis Creutzfeldt-Jacob disease (variant) Chikingunya/Dengue Ehrlichiosis Encephalitis* Hantavirus Listeriosis Lyme Disease (Borreliosis) Meningitis* Plague Q Fever Rabies Relapsing Fever Rocky Mtn. Spotted Fever Cysticercosis Tularemia West Nile Fever & Severe West Nile Disease 3/3/18 2

3 Rabies Lyssavirus in the family Rhabdoviridae All terrestrial mammals are considered to be susceptible to rabies. There are several variants (strains) and subtypes, usually named for an adapted mammalian host 3/3/18 3

4 Rabies Adapted hosts do not survive the infection, but they do survive longer and have higher numbers of virus in their saliva to increase the probability of transmission Transmission is by bite or contamination of skin wounds or mucous membranes with saliva containing the virus; very rarely by inhalation of contaminated air (caves) or by contamination of skin wounds with CSF containing the virus 3/3/18 4

5 Rabies Prevention This disease is very preventable by vaccination (both human and animal). Texas state law requires ALL dogs, cats and ferrets to be currently vaccinated against rabies. 3/3/18 5

6 Rabies Vaccination Required by state law for dogs, cats and domestic ferrets by 16 weeks of age (injectible vaccine) Other animals may be vaccinated to prevent disease, but that may not be legally recognized in a bite situation. The oral vaccine is not acceptable for dogs and cats (free-ranging wildlife only). 3/3/18 6

7 Human Anti-Rabies Biologicals Vaccine -For exposed persons who have not previously received vaccine, it is a 4 injection series on day 0, day 3, day 7 and day Exposure means a bite or scratch with salivary contact or saliva contact with any mucus membrane 3/3/18 7

8 Human Anti-Rabies Biologicals Immunoglobulin - For exposed who have not previously received a vaccination, serum is infiltrated around the bite site; total volume is determined by body weight. 3/3/18 8

9 Human Vaccination The pre-exposure series is 3 injections at day 0, day 7 and day14. An exposed person who has been previously vaccinated receives 2 booster injections at day 0 and day 3 but no immunoglobulin. Recommended for high risk occupations like veterinarians and animal control officers. 3/3/18 9

10 Diagnostic Testing of Brain Material for Rabies General diagnosis by direct fluorescent antibody (dfa) test on brain tissue Specific variant diagnosis by fluorescent monoclonal antibody. 3/3/18 10

11 3/3/18 11

12 3/3/18 12

13 Adapted Rabies Hosts in Texas There are different variants of rabies virus in West Texas - South Central Skunk - Bat (multiple strains based on bat species) - *Texas Gray Fox - *Texas Coyote/Dog (in South Texas) 3/3/18 13

14 Plague (Yersinia pestis) Sylvatic plague is somewhat common in West Texas. Plague is primarily a rodent disease. Wild carnivores can ingest infected rodents or become infected by fleas. 3/3/18 14

15 Sylvatic Plague Canids ingest infected rodents and usually develop long term antibodies. Felids can become seriously infected and can become contagious through aerosol or direct contact transmission. 3/3/18 15

16 3/3/18 16

17 Recent Plague Diagnoses June, 2016 Midland County (woodrat, culture, PCR) May, 2016 Dallam County (fleas, PCR) July, 2017 Bailey County (blacktailed prairie dogs, PCR) 3/3/18 17

18 3/3/18 18

19 Types of Human Plague Bubonic - infection in the regional lymph nodes - often seen with flea transmission Septicemic - infection in the bloodstream - source of infection for fleas Pneumonic - in the lungs - highly contagious by coughing - aerosol transmission 3/3/18 19

20 Diagnosis of Plague This may vary with the type of clinical plague encountered. Culture - blood - lymph node aspirate - sputum DFA and PCR 3/3/18 20

21 Treatment of Human Plague Fluoroquinilones (Ciprofloxacin) Gentamycin Antibiotic therapy is often successful but should be initiated as soon as possible. 3/3/18 21

22 Relapsing Fever Also called Tick Borne Relapsing fever (TBRF) This infection is caused by spirochetes of the genus Borrelia. The vectors are soft ticks of the genus Ornithodoros. 3/3/18 22

23 3/3/18 23

24 TBRF Disease In the western USA, there are 2 species that can cause infection: - Borrelia hermsii - Borrelia turicata These are vectored by specific soft ticks: - Ornithodoros hermsii found in coniferous forests at higher elevation - Ornithodoros turicata found at lower elevations 3/3/18 24

25 TBRF Symptomolgy The tick bite is often unnoticed. Soft ticks feed quickly. Primary symptoms are usually correlated with bacteremia and include: - high fever - chills - headache, myalgia, arthralgia The typical pattern is 3 days of fever followed by 7 afebrile days followed by 3 days of fever then 7 afebrile days, etc. 3/3/18 25

26 TBRF Diagnosis Spirochetemia is usually highest during febrile periods so microscopy of stained blood smears or darkfield. Serology is not standardized and may not be reliable. Can cross react with Lyme Disease tests. Culture in BSK medium prior to antibiotic treatment PCR is being developed. 3/3/18 26

27 TBRF Treatment Tetracycline is usually the primary choice. Also erythromycin and penicillin Initial antibiotic treatment may result in Jarisch-Herxheimer reaction (a worsening of symptoms within 4 hours of treatment 3/3/18 27

28 Recent research Detection of up to 50% of coyotes in Jeff Davis, Presidio and El Paso Counties (Texas) have antibodies against B. turicata. 3/3/18 28

29 Questions? 3/3/18 29

30 Thank you (915) /3/18 30