a survey of the risk of zoonoses for veterinarians

ORIGINAL ARTICLE

A Survey of The Risk of Zoonoses for VeterinariansJ. Jackson and A. Villarroel

Department of Clinical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR, USA

Impacts

• Rabies is a zoonosis not only transmitted by wildlife but also pets and

livestock. In fact, among veterinarians, domestic animals are responsible for

more exposure events than wildlife.

• Most common zoonoses are transmitted through skin contact and

transmitted by pets (especially cats).

• Training can help prevent transmission of zoonoses as evidenced by the fact

that most veterinarians suffer a zoonotic disease early in their careers, or

even during veterinary school. Consultation with a veterinarian may prove

crucial when dealing with some human diseases, especially when similar

signs are observed at a similar time in animals in close contact with the

patient. Veterinarians are trained to diagnose diseases that can affect the

public.

Introduction

A zoonosis is a disease that is maintained in animal pop-

ulations and is transmissible in either direction between

animals and humans (Acha and Szyfres, 1987). The spe-

cific term that refers to an infectious disease that is trans-

missible from animals to humans is anthropozoonosis,

while zooanthropozoonosis refers to a disease transmitted

from humans to animals. The focus of this study is on

anthropozoonoses.

Little is known about the prevalence, diagnosis and

treatment of zoonotic disease among veterinarians. A

study in New Zealand in 1976 revealed that 90% of vet-

erinarians tested positive for Brucella abortus via serol-

ogy, while only 26% of veterinarians reported having

had a dermatophyte infection (Robinson and Metcalfe,

Keywords:

Zoonoses; veterinarian; rabies

Correspondence:

J. Jackson. Department of Clinical Sciences,

College of Veterinary Medicine, Oregon State

University, Corvallis, OR 97331, USA.

Tel.: (541) 737-5853; Fax: (541) 737-6879;

E-mail: [email protected]

Results of this study were presented at the

2009 Oregon Public Health Association

(OPHA) Annual Conference in Corvallis, OR

on October 27, 2009.

Received for publication December 18, 2010

doi: 10.1111/j.1863-2378.2011.01432.x

Summary

The objectives of this study were to identify factors associated with zoonotic

infections in veterinarians, the incidence of physician consultation and treat-

ment and the incidence of diagnostic and treatment errors. Veterinarians in

any area of practice were solicited to participate in an online survey through

an invitation letter sent to the Oregon Veterinary Medical Association. Propor-

tions of respondents to various factors were analyzed for differences among

gender, age, time since graduation and type of practice in which they worked.

In all, 216 complete responses were received. In all, 13.9% of respondents had

never been vaccinated against rabies, and 20.8% had been exposed to suspect

rabid animals, mostly (64.4%) a single time. Other zoonoses were reported by

47.2% of respondents: mostly diseases transmitted via contact (57.4%) espe-

cially ringworm, followed by those with oral transmission (21.7%). Most zoo-

notic infections were reportedly acquired by young veterinarians working in

primary care veterinary practice. Cats were the species most commonly

reported as the animal source of a zoonotic infection. Veterinarians likely self-

diagnosed zoonotic diseases, especially those transmitted by contact. Medical

care providers were consulted for diagnosis of more serious diseases. Diagnosis

and treatment errors were uncommon. Results of this study emphasize the

need to educate future veterinarians during their early years in veterinary

school about the risks associated with their future jobs.

Zoonoses and Public Health

ª 2011 Blackwell Verlag GmbH 193Zoonoses and Public Health, 2012, 59, 193–201

1976). In Great Britain, a survey in 1982 revealed that

64.5% of veterinarians reported contracting one or more

zoonotic infections (Constable and Harrington, 1982),

most commonly ringworm, brucellosis and Newcastle

disease. Researchers who conducted a survey in North

Carolina in 1995 reported that 35.2% of veterinarians

had contracted a zoonotic disease (Langley et al., 1995).

The limited available information on the incidence of

contracting a zoonotic infection among veterinarians is

likely because of the variety of zoonotic diseases that can

be acquired by veterinarians, many zoonotic diseases are

not reportable, and the fact that veterinarians can usually

recognize these infections which are self-limiting or easily

treated.

Veterinarians are likely to be at higher risk for con-

tracting a zoonotic disease compared with the general

population because of the exposure to sick animals on a

daily basis. Because veterinarians are educated and trained

specifically to recognize and treat diseases in animals, they

are the professionals called upon to inspect injured and

sick animals, both domestic and wildlife. Some evidence

for this increased risk is shown in statistics collected by

the Oregon Department of Human Services of voluntary

reporting by veterinarians of animals infected with a zoo-

notic agent. In 2009, there were 161 cases of a zoonotic

disease diagnosed in dogs across Oregon (mainly giardia-

sis, leptospirosis and campylobacteriosis) and 87 cases of

a zoonotic disease in cats (mostly ringworm and giardia-

sis) (ODHS, 2010a).

Zoonotic agents can be transmitted through various

routes (Acha and Szyfres, 1987). Those transmitted via

skin contact without breaking the skin include agents

such as ringworm or sarcoptic mange mites. Diseases

requiring a break in the skin’s integrity include cat

scratch disease (Bartonella henselae), leptospirosis and

rabies. A third category includes diseases such as psittaco-

sis (Chlamydia psittaci) caused by agents that are aerosol-

ized and inhaled. The oral or ingestion route includes a

large number of zoonotic agents such as Salmonella, cryp-

tosporidia and Campylobacter spp. Another possible route

is ocular exposure to agents such as Chlamydia.

Rabies is a special zoonotic disease in that once clinical

signs become evident (indicating the virus has reached

the nervous system), there is no cure and the disease is

almost invariably fatal, both for animals and humans

(Acha and Szyfres, 1987; Anonymous 2004). However, the

disease can be prevented when an individual bitten by a

suspect rabid animal is treated prior to the virus reaching

the nervous system (prophylactic treatment) (NASPHVC,

2008). A study in the United States in 2009 indicated

there were 6690 reported cases of rabies in animals (Blan-

ton et al., 2010); 93% were in wildlife and 7% were in

domestic animals.

The objectives of this study were (i) to identify factors

associated with zoonotic infections in veterinarians in

Oregon, (ii) to determine the proportion of veterinarians

that seek medical care from a medical care provider and

(iii) to determine the incidence of diagnostic and treat-

ment errors. Because of the special circumstances of

rabies infection (transmission route, potential latency and

fatality), this zoonosis was studied separately from the

other zoonoses.

Materials and Methods

Study protocol

The study was conducted as a cross-sectional descriptive

study of veterinarians licensed in the State of Oregon. An

online survey was developed and made available to all

veterinarians (active and retired) in any area of veterinary

practice. The study protocol was deemed as exempt from

review by the institutional review board of Oregon State

University (IRB # 3894).

Survey development

Survey questions were developed to solicit information on

zoonotic diseases contracted by the respondents. The sur-

vey was tested by faculty and veterinary students from

Oregon State University, and changes and recommenda-

tions were included in the final version of the survey. The

final questionnaire consisted of nine questions for all

respondents, with an additional four questions for veteri-

narians reporting exposure to a suspect rabid animal, and

an additional 10 questions for each zoonotic disease

selected.

Survey questions were organized into three sections.

The first section solicited information on demographic

data including age, gender and year of graduation from

veterinary school. Section two included questions specific

to rabies, such as vaccination status and exposure to sus-

pect rabid animals, including when (year) and where the

exposure occurred (multiple-choice), what animal species

was involved (multiple-choice) and its disposition after

the exposure (multiple-choice). The term ‘exposure’ to a

suspect rabid animal was not specifically defined in the

survey but left open to the interpretation of the respon-

dents (no laboratory confirmation was required). The

third section solicited information regarding all other

zoonoses that were contracted while practicing as a

licensed veterinarian. An initial multiple-choice question

required respondents to select all zoonotic diseases they

had experienced. Each selected zoonotic disease prompted

a list of questions pertaining to the animal species it was

contracted from (multiple-choice), when (year) and

where the infection occurred (State or country if outside

Zoonoses among Veterinarians J. Jackson and A. Villarroel

194 ª 2011 Blackwell Verlag GmbH

Zoonoses and Public Health, 2012, 59, 193–201

the USA and county if in Oregon), the type of practice in

which the respondent was working (multiple-choice),

whether the veterinarian (if woman) was pregnant at the

time (yes versus no), who determined the diagnosis (self-

diagnosis or medical care provider), diagnostic procedures

(multiple-choice), whether there were diagnostic errors

(yes versus no) or medication errors (yes versus no) and

whether the infection resolved or became chronic.

Survey distribution

An invitation letter containing a link to the survey was

distributed to the 1450 veterinarians licensed to practice

in the State of Oregon through an email distributed by

the Oregon Veterinary Medical Examining Board and a

printed invitation in the Oregon Veterinary Medical Asso-

ciation newsletter. The Web link remained accessible for

participation from June 16, 2008 through September 5,

2008. A reminder email was sent in August to improve

response rate.

Data analysis

Descriptive statistics were performed for all studied out-

comes. Respondents were categorized according to age

into four generational categories following the definitions

of the American Association of Retired Persons (Rimkus

and Melinchok, 2005). Generational categories included

the silent generation (‡62 years old, born before 1946),

baby boomer generation (43–61 years old, born between

1946 and 1964), generation X (31–42 years old, born

between 1965 and 1978), and generation Y (£30 years

old, born after 1978).

Year of graduation was used to categorize respondents

into groups on the basis of number of years of profes-

sional practice experience. Categories consisted of recent

graduates (1–2 years since graduation), skilled veterinari-

ans (3–5 years since graduation), experienced veterinari-

ans (6–12 years since graduation), and seasoned

veterinarians (>12 years since graduation). Limits for the

categories were selected after consultation with private

practitioners on the perceived professional skills of gradu-

ate veterinarians.

Cross-tabulations were performed to evaluate the risk

of zoonotic disease across categories such as gender, gen-

erational group, years of veterinary experience and type

of veterinary practice. A standard Z test was performed to

determine whether there was a difference between the

proportions of respondents in one category versus

another. The level of significance for these comparisons

was established at 5%. For analyses that involved compar-

ison of >2 categories, such as comparisons between gen-

erational categories or practice experience categories, a

Bonferroni correction was used to preserve an overall avalue of 0.05. All statistical analyses were performed using

statistical software (Minitab 15, Minitab Inc., State Col-

lege, PA, USA).

Results

A total of 315 responses were received to the survey for a

response rate of 21.7% (315/1450). Responses that did

not answer the main questions pertaining demographics,

whether or not they had been exposed to rabid animals,

whether or not they had experienced a zoonotic infection

and which one were identified as incomplete responses

(n = 99) and were eliminated, leaving 216 responses for

the analyses for a 14.9% (216/1450) completed response

rate. Female veterinarians accounted for 67.6% (146/216)

of completed responses, while male veterinarians

accounted for 32.4% (70/216) of completed responses.

Gender distribution of respondents varied by generational

group (Fig. 1). No female veterinarians reported having

been pregnant at the time of experiencing a zoonosis. Age

and veterinary experience were highly correlated

(r = 0.918), and because of small sample size, the actual

influence of both factors could not be quantified.

Rabies

Not all veterinarians who responded to the survey were

vaccinated against rabies. In all, 86.1% (186/216) had

been vaccinated against rabies, while 13.9% (30/216) were

not. Non-vaccinated veterinarians included 25 currently

working in clinical practice (private or academic), two in

shelter/relief practice, two working for the government

and one retired.

30%

40%

50%

60%

70%

80%

90%

100%

Per

cen

tag

e o

f re

spo

den

ts

MenWomen

0%

10%

20%

Silent Gen Baby Boomers Gen X Gen Y

Fig. 1. Classification by gender and generational category for respon-

dents (n = 216) to an online survey on the risk of zoonoses in veteri-

narians licensed in Oregon.

J. Jackson and A. Villarroel Zoonoses among Veterinarians


There was no difference (P = 0.455) in the proportion

of veterinarians that were not vaccinated against rabies

among men (17.1%) and women (12.3%). Small sample

size in some of the generational categories and type of

veterinary practice resulted in no significant differences in

the proportion of veterinarians not vaccinated against

rabies in each category (Table 1).

A total of 20.8% (45/216) of survey respondents had

been exposed to a suspect rabid animal at least once dur-

ing their careers. Similar proportions of men [25.7% (18/

70)] and women [18.5% (27/146)] veterinarians were

exposed to rabies (P = 0.296). There was also no differ-

ence between the proportion of vaccinated [22.0% (41/

186)] and non-vaccinated veterinarians [13.3% (4/30)]

that had been exposed to suspect rabid animals

(P = 0.397). Most of the exposures [80.0% (36/45)] were

reportedly within the United States. However, exposure

to suspect rabid animals within the State of Oregon

accounted only for 38.9% (14/36) of the domestic expo-

sures, with the rest of the exposures occurring throughout

additional 14 states. The 14 exposures in Oregon were

reported in eight different counties, including Benton (2

cases), Coos (1), Deschutes (1), Klamath (2), Lincoln (1),

Marion (4), Multnomah (1) and Washington county (1),

with 64.3% (9/14) of the reported exposures occurring in

the north-western corner of Oregon.

The majority of veterinarians were exposed only once

[64.4% (29/45)]; 8.9% (4/45) were exposed twice and

11.1% (5/45) three times, and 15.6% (7/45) were exposed

five times or more (three men and four women). Respon-

dents who reported multiple exposures to suspect rabid

animals were typically those who had worked in foreign

countries or with wildlife. Overall, exposure to rabies

involved a variety of animal species, with domestic species

yielding the largest percentage of exposures [53.3% (24/

45)], followed by wildlife species [28.9% (13/45)]. Four

respondents (8.9%) reported the animal species as other

than those listed in the multiple-choice option and could

not be classified as wildlife or domestic. Another four

respondents (8.9%) did not report the animal species

involved in the exposure. Domestic species reported as

rabies exposures included horses (8), dogs (7), cattle (5),

cats (4) and sheep (1). There was no categorization of the

wildlife animal species. Disposition of the suspect rabid

animal included euthanasia (n = 24), deceased at time of

exposure (n = 10) or quarantine (n = 5). There was no

indication of the suspected animal’s disposition from six

respondents.

Common zoonoses

Overall, 47.2% (102/216) of survey respondents reported

having experienced a zoonotic disease. The proportion of

women affected was 47.9% (70/146), which did not differ

from the 45.7% (32/70) of men infected with a zoonotic

disease (P = 0.814). There was a difference between gen-

erational groups; generation Y veterinarians reported

fewer infections at 21.7% (5/23) compared with veterinar-

ians of generation X [48.6% (51/105), P = 0.034] and

baby boomers [53.9% (41/76), P = 0.013]. Recent gradu-

ates reported no zoonotic infections [0.0% (0/8)], which

was significantly different from the 46.9% (30/64) of

experienced veterinarians (P = 0.031) and the 53.7% (65/

121) of seasoned veterinarians (P = 0.10) who reported

having suffered a zoonotic disease.

Sample size was insufficient for continued stratified

analysis of the risk of zoonoses in veterinarians of the

various groups of experience within each generational

group. However, analysis of the risk of zoonotic infection

by time since graduation from veterinary school revealed

that most zoonotic infections reportedly happened in the

first 3 years after graduation and during senior year in

veterinary school (Fig. 2).

Most veterinarians [65.7% (67/102)] reported a single

zoonotic disease, 23.5% (24/102) reported experiencing

two zoonotic diseases, 6.9% (7/102) experienced three

diseases and 3.9% (4/102) reported experiencing four or

more diseases. The 102 veterinarians who reported zoo-

notic infections described 148 events. The various zoo-

notic diseases reported by the survey respondents were

grouped into four routes of transmission: contact, skin

break, inhalation and oral exposure. Types of exposure by

order of frequency were: 57.4% (85/148) via contact,

Table 1. Demographic characteristics according to vaccination status

against rabies for 216 respondents to an online survey about the risk

of zoonoses among veterinarians licensed in the State of Oregon

Vaccination status against rabies

Vaccinated

No. (%)

Not vaccinated

No. (%)

All respondents 186 (86.1) 30 (13.9)

Gender

Men 58 (82.9) 12 (17.1)

Women 128 (87.7) 18 (12.3)

Generational category (years)

Silent generation (‡62) 9 (75.0) 3 (25.0)

Baby boomers (43–61) 63 (82.9) 13 (17.1)

Generation X (30–42) 95 (90.5) 10 (9.5)

Generation Y (<30) 19 (82.6) 4 (17.4)

Practice type

Academia 18 (94.7) 1 (5.3)

Clinical 149 (86.1) 24 (13.9)

Government 5 (71.4) 2 (28.6)

Industry 1 (100.0) 0 (0.0)

Laboratory 7 (100.0) 0 (0.0)

Other 6 (66.7) 3 (33.3)




21.6% (32/148) by oral exposure, 15.5% (23/148) via skin

breaks and 5.4% (8/148) via inhalation (Fig. 3). Several

animal species were reported as the likely source of the

various zoonotic infections: cats accounted for 55.6% (30/

54) of reported transmissions, followed by cattle [13.0%

(7/54)], dogs [11.1% (6/54)], birds [5.5% (3/54)], horses

[3.7% (2/54)], small ruminants [1.9% (1/54)] and other

animal species [7.4% (4/54)]. Descriptive statistics of

diseases reported by veterinarians participating in the sur-

vey are presented in Table 2.

Only 52.9% (54/102) of veterinarians reported the type

of practice they were engaged in at the time of infection

with the zoonotic disease: 66.7% (36/54) were in private

practice, 11.1% (6/54) in academia, 11.1% (6/54) in vet-

erinary school (students), 9.3% (5/54) worked in specialty

veterinary care and 1.9% (1/54) in government. Limited

data on regional distribution prevented from analysis of

where veterinarians were most likely infected with the

most common zoonoses. Additionally, the ubiquitous

nature of reported diseases rendered further analyses

futile.

Physician consultation

The final objective of the survey pertained to the likeli-

hood of seeking assistance of a medical care provider for

diagnosis and treatment of a zoonotic disease. Descriptive

statistics of reported physician consultation and misdiag-

nosis of zoonotic diseases reported by veterinarians par-

ticipating in the survey are presented in Table 3.

Information about physician consultation was only avail-

able for 55 respondents; [56.4% (31/55)] of veterinarians

did not contact a physician to diagnose or treat their

zoonotic infection, while 43.6% (24/55) did (P = 0.253).

Veterinarians more commonly self-diagnosed diseases

transmitted via contact [72.2% (26/36)], whereas physi-

cians were more likely consulted for diagnosis of diseases

Table 2. Zoonotic diseases reported by participants in an online survey about the risk of zoonoses among veterinarians licensed in the State of

Oregon

Route of transmission Zoonotic disease

No. (%)

Infections

Animal species (No.)

Bird Cat Cattle Dog Horse

Small

ruminant Wildlife Other

Not

reported

Rabies [45/216 (20.8%)exposed] – 0 4 5 7 8 1 12 4 4

Other zoonoses 148 (100.0) 3 31 7 6 2 1 – 4 94

Contact Ringworm 80 (54.1) 1 22 4 4 1 – – 1 47

Sarcoptic mange 5 (3.4) – 2 – – – – – – 3

Oral Campylobacteriosis 3 (2.0) – – 2 – – – – – 1

Cryptosporidiosis 7 (4.7) – – 1 – 1 – – 1 4

Giardiasis 13 (8.8) – – – 2 – – – 2 9

Listeriosis 1 (0.7) – – – – – – – – 1

Roundworm infestation 1 (0.7) – 1 – – – – – – –

Salmonellosis 5 (3.4) – – – – – 1 – – 4

Toxoplasmosis 2 (1.4) – – – – – – – – 2

Skin break Brucellosis 2 (1.4) – – – – – – – – 2

Cat scratch fever 15 (10.1) – 5 – – – – – – 10

Leptospirosis 1 (0.7) – – – – – – – – 1

Pasteurellosis 4 (2.7) – 1 – – – – – – 3

Tularaemia 1 (0.7) – – – – – – – – 1

Inhalation Histoplasmosis 1 (0.7) – – – – – – – – 1

Psittacosis 4 (2.7) 2 – – – – – – – 2

Q fever 2 (1.4) – – – – – – – – 2

Tuberculosis 1 (0.7) – – – – – – – – 1

‘–’ Not available

30%

25%

15%

20%

10%

5%Pro

po

rtio

n o

f zo

on

oti

c in

fect

ion

s

Years since graduation

0%–1 0 1 2 3 4 5 6 7 8 9 10+

Fig. 2. Time at which zoonotic infections other than rabies were

acquired relative to graduation from veterinary school.



transmitted by skin breaks [100.0% (6/6)] and inhalation

[100.0% (2/2)] (Fig. 4). Physicians were consulted for

diagnosis and treatment of 54.5% (6/11) of diseases with

oral transmission.

Physicians were more likely to perform diagnostic pro-

cedures [54.2% (13/24)] compared with veterinarians

[12.9% (4/31), P = 0.003]. Diagnostic errors were

reported by 20.8% (5/24) of veterinarians who consulted

a physician, compared with 6.5% (2/31) of those that

self-diagnosed their zoonotic disease (P = 0.238). Similar

proportions reported the use of wrong treatment by phy-

sicians [16.7% (4/24)] and self-diagnosing veterinarians

[6.5% (2/31)]. All respondents confirmed resolution of

their condition. However, one respondent described a

case of campylobacteriosis acquired during senior year in

veterinary school that exacerbated a pre-existing condi-

tion of ulcerative colitis, resulting in colectomy.

Discussion

Rabies

The finding that 13.9% of responding veterinarians were

not vaccinated against rabies was surprising because

most veterinary colleges require vaccination of students

at enrolment. It was not possible to determine whether

non-vaccinated veterinarians had graduated from a spe-

cific college within the USA or even whether they were

foreign graduates. Most of the non-vaccinated veterinari-

ans (25/30) worked in clinical practice, which could lead

to exposure to suspect rabid animals. Although the

majority of veterinarians that were exposed to suspect

rabid animals only experienced one exposure, not being

vaccinated is likely an unnecessary risk, given that this

disease is untreatable and nearly always fatal (effective

treatment has been reported only in one case) (Anony-

mous 2004, NASPHVC, 2008). One explanation for why

some veterinarians may not see an immediate need to

be vaccinated is the low prevalence of rabies reported in

domestic animal species in Oregon between 1990 and

2008 (0.25% in cats and 0.01% in dogs) compared with

that in wildlife (9.8% in bats and 27% in foxes) (ODHS,

2010b). However, most of the exposures reported by

survey respondents were because of domestic animal

species, a finding that conflicts with a previous report

on rabies surveillance in the USA that found that most

human exposures were because of wildlife (Blanton

et al., 2010), although this study refers to the general

public, not specifically veterinarians. Our survey did not

specifically ask under which circumstance suspect rabid

domestic animals were encountered by veterinarians.

Therefore, it is unclear whether these animals were pets

or stray animals, which likely have different exposure

risks.

Although most veterinarians who had been exposed to

suspect rabid animals reported a single exposure, seven

veterinarians reported exposure to multiple suspect rabid

Table 3. Consultation of medical care providers for diagnosis of zoonotic infections, self-diagnosis, and diagnostic errors reported by participants

in an online survey about the risk of zoonoses among veterinarians licensed in the State of Oregon

Route of transmission Zoonotic disease

No. (%)

Infections

Physician consultation (No.) Diagnostic error (No.)

No Yes

Not

reported No Yes

Not

reported

Total zoonotic infections reported 148 31 24 93 47 7 94

Contact Ringworm 80 (54.1) 26 9 46 31 2 47

Sarcoptic mange 5 (3.4) – 2 3 1 1 3

Oral Campylobacteriosis 3 (2.0) – 2 1 1 1 1

Cryptosporidiosis 7 (4.7) 1 2 4 3 – 4

Giardiasis 13 (8.8) 2 2 9 4 – 9

Listeriosis 1 (0.7) – – 1 – – 1

Roundworm infestation 1 (0.7) 1 – – 1 – –

Salmonellosis 5 (3.4) 1 – 4 1 – 4

Toxoplasmosis 2 (1.4) – – 2 – – 2

Skin break Brucellosis 2 (1.4) – – 2 – – 2

Cat scratch fever 15 (10.1) – 5 10 3 2 10

Leptospirosis 1 (0.7) – – 1 – – 1

Pasteurellosis 4 (2.7) – 1 3 1 – 3

Tularaemia 1 (0.7) – – 1 – – 1

Inhalation Histoplasmosis 1 (0.7) – – 1 – – 1

Psittacosis 4 (2.7) – 2 2 1 1 2

Q fever 2 (1.4) – – 2 – – 2

Tuberculosis 1 (0.7) – – 1 – – 1




animals. Explanation for these multiple exposures

included working in underdeveloped countries (where

rabies is not controlled by vaccination), working with

wildlife or in a veterinary diagnostic laboratory. All veteri-

narians responding to our survey who had multiple rabies

exposures had been vaccinated against rabies.

In summary, prophylactic vaccination against rabies

should be encouraged for all veterinarians, whether they

work with wildlife or domestic animals. Additionally, vac-

cination titres should be monitored regularly to provide

evidence of active immune status against this fatal disease

(Rupprecht et al., 2010).

Common zoonoses

As evidenced by the results of this survey, veterinarians are

at high risk for contracting zoonotic infections. Almost half

of respondents reported having had a zoonotic infection

other than rabies. Because veterinary experience and age

were highly correlated, the effect of both could not be dif-

ferentiated. Young veterinarians (generation Y) and recent

graduates reported a lower incidence of zoonoses as com-

pared with older veterinarians (Generation X and baby

boomers) and those that were experienced and seasoned

veterinarians. The higher risk in older veterinarians could

be explained by a longer career and therefore a higher

cumulative exposure to potential zoonoses transmission.

However, most zoonotic infections were reported to hap-

pen during senior year in veterinary school and the first

3 years after graduation (Fig. 2), which emphasizes the

need for proper education in recognizing zoonotic diseases

in veterinary patients, as well as in preventing transmission

of these diseases from animal patients. Although veterinary

students have been reported to suffer from infections with

sporadic gastrointestinal pathogens such as Cryptosporidi-

um parvum and Salmonella spp. when first exposed to ani-

mals on a farm setting (NASPHV, 2011), only two and

three individuals (respectively) reported those diseases in

this survey. It is possible that other respondents failed to

recall the disease because of its self-limiting nature and the

likelihood of mild symptoms (recall bias). Additionally, it

is possible that sporadic gastrointestinal diseases were

because of foodborne infection. In the end, given that most

of the zoonotic infections were reported by seasoned veteri-

narians, it could be inferred that education and training on

zoonotic disease recognition and transmission prevention

has improved over the years, because no recent graduates

(1–2 years after graduation) and few skilled veterinarians

(3–5 years after graduation) reported zoonotic infections.

Most zoonotic infections were reportedly contracted

while working in primary care. This likely reflects that the

majority of veterinarians work in primary care (AVMA,

2010), and the fact that primary care veterinarians would

see most of the animals in direct contact and before send-

ing them to a specialist. Because the most commonly

reported zoonotic infection was ringworm, transmission

via skin contact was the most common transmission

route (57.4%) reported in this survey. Additionally, cats

were the species most commonly implicated in the trans-

mission of zoonotic infections, likely due to frequent

diagnosis of ringworm in this species. These results likely

support findings of a study of veterinary infection control

practices in the United States in 2005 that showed that

only 17.8% of small animal veterinarians wore protective

clothing and gloves when handling an animal with der-

matologic signs (Wright et al., 2008).

Physician consultation

Overall, 56.4% of veterinarians reported self-diagnosing

zoonotic infections. Self-diagnosis was more likely for dis-

eases transmitted via contact, while diseases transmitted

90%

100%PhysicianSelf-diagnosis

70%

80%

50%

60%

30%

40%

10%

20%

0%Contact Oral Inhalation Skin break

Pro

po

rtio

n o

f zo

on

oti

c in

fect

ion

s

Fig. 4. Comparison of routes of transmission of zoonotic infections

diagnosed by physicians versus self-diagnosed by veterinarians.

90%

100%

70%

80%

50%

60%

70%

40%

50%

20%

30%

0%

10%

Contact Oral Skin break Inhalation Ocular

Pro

po

rtio

n o

f zo

on

oti

c in

fect

ion

s

Transmission route

Fig. 3. Proportion of zoonotic infections acquired by veterinarians

licensed in the State of Oregon categorized by route of transmission.



via inhalation or skin break were more likely consulted

on with a physician. This is likely because the most com-

monly reported disease was ringworm, which is easily rec-

ognized by veterinarians and usually presents low

pathogenicity and is self-limiting.

Although numerically higher percentage of zoonotic

diseases were reportedly misdiagnosed and mistreated by

physicians compared with self-diagnosing veterinarians,

there was no statistical significance in this comparison

because of limited sample size. Diagnostic error was not

defined in the survey, but likely determined by the

respondents because of lack of resolution of the condition

until new treatment was established. Additionally, physi-

cians were more likely to perform diagnostic tests com-

pared with self-diagnosing veterinarians. These differences

are likely because physicians were called upon to make

definitive diagnoses and work on diseases with potentially

serious consequences such as cat scratch disease and psit-

tacosis, compared with veterinarians working based on

presumptive diagnosis of diseases less likely to have seri-

ous consequences such as ringworm.

Once a zoonotic infection has been contracted, the most

reasonable course of action is to consult a physician, the

professional trained to diagnose and treat human disease,

and who knows better potential pharmacological problems

and interactions that can arise with treatment in humans.

There have been reports of veterinarians having a hostile

or passive-aggressive attitude towards physicians (Marcus,

2004) likely attributable to the self-reported lack of

knowledge about zoonotic diseases among physicians

(Grant and Olsen, 1999) and sometimes condescending

demeanour of some physicians towards veterinarians

(Marcus, 2004). Open communication with the physician

about the presumptive self-diagnosis made by the

veterinarian can help expedite the definitive diagnosis and

effective treatment and consolidate education of local phy-

sicians in zoonotic diseases that could later help diagnosis

and treatment in other people.

Additionally, because zoonoses are transmissible

between animals and humans, veterinarians may expose

new patients to a zoonotic disease and through them may

expose the patients’ owners, their clients. This can lead to

some legal problems such as negligent failure to diagnose

a zoonotic disease in an animal, or failure to advise a cli-

ent to seek care from a physician in the case of a poten-

tial zoonotic exposure (Babcock et al., 2008).

Although all surveys are subject to recall bias, which

gets worse as time between the surveyed event and survey

time increase, we believe the results of this study repre-

sent the big picture of zoonoses among veterinarians.

Recall bias tends to have respondents most likely remem-

ber traumatic circumstances, such as a complicated infec-

tion may be. However, the fact that most of the recalled

zoonotic infections were reported to happen during the

years immediately before and after graduation from veter-

inary school seems to lessen the potential impact of recall

bias in this study. A survey response rate of 21.7% is the

major limitation of this study but can be viewed as repre-

sentative when compared with the commonly used figure

of 10% when testing a sample population to establish

baseline prevalence.

Results of this study emphasize the high risk of acquisi-

tion of a zoonotic disease by veterinarians, especially

those in primary care practice working with cats and dur-

ing the first few years after graduation. The risks beyond

acquisition of zoonotic infections should be considered,

such as transmission of that disease to other patients, or

even to clients, co-workers and family members. Preven-

tion starts with proper education on the mode of trans-

mission of zoonotic infectious agents and methods to

prevent the spread of these agents (Elchos et al., 2008).

The inclusion of public health courses in the veterinary

curriculum, as emphasized in the past few years, shows

the acceptance of the importance of recognizing and pre-

venting transmission of zoonotic diseases.

Acknowledgements

We want to thank the Oregon Veterinary Medical Associ-

ation and the Oregon Veterinary Medical Examining

Board for distributing this survey via email and newsletter

to their members.

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a survey of the risk of zoonoses for veterinarians

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