Click here to load reader

RABIES CONTROL PREVENTION EPIDEMIOLOGY REPORT RI ... also develop rabies. Animals such as rodents, rabbits, squirrels and opossums rarely acquire rabies and are considered (low-risk

  • View
    0

  • Download
    0

Embed Size (px)

Text of RABIES CONTROL PREVENTION EPIDEMIOLOGY REPORT RI ... also develop rabies. Animals such as rodents,...

  • 1

    RRAABBIIEESS CCOONNTTRROOLL && PPRREEVVEENNTTIIOONN

    EEPPIIDDEEMMIIOOLLOOGGYY RREEPPOORRTT

    RRII 22000088--22000099

    AAUUGGUUSSTT 22001100 RRII DDEEPPAARRTTMMEENNTT OOFF HHEEAALLTTHH

    DDIIVVIISSIIOONN OOFF IINNFFEECCTTIIOOUUSS DDIISSEEAASSEE && EEPPIIDDEEMMIIOOLLOOGGYY

    BACKGROUND

    Since its arrival in 1994, the mid-Atlantic raccoon-adapted strain of the rabies virus has become enzootic

    (endemic) among the wild animal population throughout Rhode Island. Animals with the greatest

    susceptibility to this strain are raccoons, with spill over into the skunk, fox, woodchuck and other

    terrestrial mammal populations (also called high-risk, target or vector species). Unimmunized

    (therefore susceptible) pets such as cats, dogs and ferrets (medium-risk or suspicious species) and strays

    can acquire rabies through exposure to wildlife. Cattle, sheep, pigs, horses and other farm animals can

    also develop rabies. Animals such as rodents, rabbits, squirrels and opossums rarely acquire rabies and

    are considered (low-risk species). Bats in RI are also endemic for the bat strain of rabies virus.

    Humans may be exposed to the rabies virus through a bite, scratch or direct contact, where there is

    contamination of a scratch, abrasion, mucous membrane, or fresh open wound with potentially infectious

    material such as saliva or central nervous system tissue from an animal. The majority of such exposures

    are from dog bites or cat bites/scratches. Often indirect exposures occur, such as when fresh saliva from a

    target species is carried passively in a wound or on the muzzle or fur of a pet animal. Exposure by

    inoculation of a mucous membrane (nose, eyes) or into an open skin lesion or wound of the human

    caretaker is, theoretically possible in such a situation. Of note, bat rabies strains are highly transmissible

    to humans, and prophylaxis is often recommended for exposure by proximity even without a visible

    wound, if the bat is not available for testing.

    The clinical and public health management of a person who may have been exposed to rabies requires first

    the assessment of whether a significant bite or non-bite exposure has occurred, and then an assessment of

    the likelihood that the animal involved was rabid. To this end, it is extremely important to capture the

    exposing animal for quarantine, or euthanasia and testing. 10-day quarantine is the recommended option

    only in the case of a captive dog or cat or ferret, which appears healthy. This action is based on the

    biologic fact that cats, dogs and ferrets shed rabies virus in the saliva only for the 10-day period

    immediately prior to death. A dog, cat or ferret that is alive and well at the end of a 10-day period of

    observation counting from the date of exposure could not have transmitted rabies to the patient. The

    authority and operational enforcement of all animal control procedures occurs under regulations and

    guidelines from the RI State Veterinarian and the Governor’s Rabies Control Board. The RI State

    Epidemiologist represents the Department of Health at this Board along with representatives from the RI

    Veterinary Medical Society, Association of Animal Control Officers, RI SPCA, RI Division of Fish and

    Wildlife, and Association of Livestock Farmers.

    Target species (or pets with clinical rabies symptoms) should be euthanized and tested as soon as

    possible, with vaccination decisions based on results. Exposures by animals that escape capture, as

    well as all low-risk species, livestock and exotic animals should be assessed on a case-by-case basis in

    consultation with public health experts. The Division of Infectious Disease epidemiology maintains a

    24/7 on call system to accept and case-manage animal exposure reports from health care providers and

  • 2

    other community sources, and provides expert consultation including pre-authorization for vaccine on

    a case-by-case basis. Post-exposure vaccination is recommended in accordance with national

    guidelines from the Advisory Council for Immunization Practice

    (http://cdc.gov/mmwr/preview/mmwrhtml/rr5902a1.htm). Also see the algorithm for management of a

    suspected rabid animal on last page of this document (Appendix A).

    ANIMAL RABIES TESTING:

    The RI Department of Health’s Division of Laboratories (Molecular Biology Lab) is the only lab in the

    state that performs animal rabies testing. Currently rabies testing is performed in response to animal-

    to-human exposure situations or animal-to-animal exposure such as pets and farm animals.

    Surveillance testing without human or pet exposure may be performed in special situations.

    A total of 872 specimens were tested for rabies in 2008 and 2009 (460 in 2008 and 412 in 2009).

    There were 79 rabid animals (34 in 2008 and 45 in 2009) identified, with 9.0% of all animals examined

    were positive for rabies. Wild species (including bats) that tested positive for rabies accounted for

    97.5% of the total while only 2.5% of domestic animals (1 cat and 1 horse) tested positive (Table 1

    and Figure 1).

    Data on animal rabies from 1994 to 2009 can be found archived at: http://www.health.ri.gov/disease/communicable/rabies/surveillance.php

    Table 1. R. I. State Health Laboratory, Rabies Testing Results by Species, 2008 - 2009

    Animal Species Tested

    n (%)

    Positive

    n (%)

    Positivity-

    Rate

    Tested

    n (%)

    Positive

    n (%)

    Positivity-

    Rate

    Cat 108 (23.5%) 1 (2.9%) 0.9% 91 (22.1%) 0 (0.0%) 0.0%

    Dog 34 (7.4%) 0 (0.0%) 0.0% 43 (10.4%) 0 (0.0%) 0.0%

    Bat 209 (45.4%) 7 (20.6%) 3.3% 161 (39.1%) 10 (22.2%) 6.2%

    Skunk 42 (9.1%) 12 (35.3%) 28.6% 40 (9.7%) 13 (28.9%) 32.5%

    Raccoon 27 (5.9%) 9 (26.5%) 33.3% 48 (11.7%) 19 (42.2%) 39.6%

    Fox 9 (2.0%) 4 (11.8%) 44.4% 10 (2.4%) 1 (2.2%) 10.0%

    Woodchuck 13 (2.8%) 0 (0.0%) 0.0% 6 (1.5%) 1 (2.2%) 16.7% Other* 18 (3.9%) 1 (2.9%) 5.6% 13 (3.2%) 1 (2.2%) 7.7%

    Total 460 (100%) 34 (100%) 7.4% 412 (100%) 45 (100%) 10.9%

    2008 2009

    • Includes 1 coyote (2008), 1 fisher cat (2009), 7 goats (3 in 2008; 4 in 2009), 3 horses (1 in 2008; 2 in 2009), 1 mink (2009), 4 opossums (all in 2008), 6 rabbits (5 in 2008; 1 in 2009), 1 rat (2009), 2 sheep (1 in 2008; 1 in

    2009), 3 squirrels (2 in 2008; 1 in 2009), 1 weasel (2009) and 1 wolf (2008)

    • These numbers represent burden of public health laboratory work contributed to by rabies prevention efforts, and are not meant to represent systematic surveillance.

  • 3

    Figure 1. State Health Laboratory Positive Rabies Tests by Animal Species,

    RI 2008 - 2009

    1 1

    12

    9

    1 1 1

    10

    13

    19

    7

    4

    0

    4

    8

    12

    16

    20

    Cat Fisher Horse Woodchuck Fox Bat Skunk Raccoon

    Animal Type

    N u

    m b

    e r

    o f

    P o

    s it

    iv e R

    a b

    ie s T

    e s ts

    2008 2009

    ANIMAL EXPOSURE TO HUMANS:

    For the purpose of this report, animal exposures are defined as bites, proximity to bats, scratches or

    abrasions, or contact of animal saliva with a wound, lesion or mucous membrane. Animal exposures

    to humans are reportable to the Division of Infectious Disease Epidemiology (Rabies Control and

    Prevention Program) 24/7. Once an animal bite or suspect exposure is reported, public health staff

    provides case-management services until final resolution of the case. These services include exposure

    evaluation, confirmation of animal capture and quarantine or confirmation of animal capture and

    euthanasia, coordination with the laboratory for follow up on animal testing results, notification to the

    patient of the status of the investigation, rabies risk assessment and communication to the patient and

    release/referral for vaccine and RIG as indicated. Follow up on completion of treatment with dates is not

    monitored. Animal exposure reports and case management notes are collected on a standardized form and

    data is maintained in a database (NEDSS). A single animal may result in multiple persons being exposed

    (most commonly with household bat exposures). Each person is counted individually as an exposure.

    Reported Animal Exposures in Rhode Island

    The average age of reported animal exposure cases was 37.4 years (37.9 years in 2008 and 36.9 years

    in 2009; Table 2). The majority of the cases (57.9%) were women (58.4% in 2008 and 57.3% in

    2009). For both years, low/no risk animal exposures comprised the majority of reports, while 29.1% of

    the reports were for high-risk animal exposures (29.1% in 2008 and 29.2% in 2009).

  • 4

    Table 2. Characteristics of Animal Exposure Reports, R.I. 2008 - 2009

    2008

    n = 1471

    2009

    n = 1360

    Total

    N = 2831

    Age*, years

    mean (σ) 37.9 (39.0) 36.9 (37.1) 37.4 (38.1)

    Gender † , n (%)

    Female 857 (58.4%) 778 (57.3%) 1635 (57.9%)

    Male 611 (41.6%) 580 (42.7%) 1191 (42.1%)

    Exposure risk ‡ , n (%)

    H

Search related