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A survey of zoonotic diseases contracted by South African veterinarians

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  • James Cook University & University of Pretoria

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A survey of 88 veterinarians employed at the Faculty of Veterinary Science, University of Pretoria, South Africa, was carried out to investigate the occurrence of zoonotic diseases among South African veterinarians. The survey found that 63.6% of veterinarians interviewed had suffered from a zoonotic disease. Veterinarians predominantly involved in farm animal practice were 3 times more likely to have contracted a zoonotic disease than those working in other veterinary fields. Fifty-six percent of disease incidents were initially diagnosed by the veterinarians themselves. Fifty-three percent of incidents required treatment by a medical practitioner, but the majority (61%) of incidents did not require absence from work. The incidence density rate for contracting a zoonotic disease was 0.06 per person year of exposure. Kaplan-Meier survival analysis estimated that the probability of having contracted a zoonotic disease was 50% after 11 years in practice. The risk of contracting a zoonotic disease appeared to be higher early in practice. The most common mode of transmission was by direct contact. Approximately 46% of South Africans still live in rural areas and regularly come into close contact with farm animals. The implications of this in the light of this survey's results are discussed.
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72 0038-2809 Tydskr.S.Afr.vet.Ver. (2003) 74(3): 72–76
Article — Artikel
A survey of zoonotic diseases contracted by South African veterinarians
B Gummow
a
INTRODUCTION
Many of the human diseases that are
new, emerging and re-emerging at pres-
ent, are caused by pathogens that origi-
nate from animals or products of animal
origin
2
. These include transmissible
spongiform encephalopathies, entero
-
haemorrhagic E. coli, Hantavirus infec
-
tions, Napah virus infections, West Nile
viralencephalitisandInfluenzaAviruses.
The World Health Organisation (WHO)
defines zoonoses as ‘those diseases and
infections that are naturally transmitted
between vertebrate animals and man’.
It has long been known that zoonotic
diseases can rapidly cause extensive
human suffering and death. For example,
during an outbreak of Rift Valley fever in
Kenya in 1997/98
8
, 89 000 cases and 150–
250 deaths were reported.
On the other hand, zoonoses can mani
-
fest as non-dramatic erosive diseases,
such as taeniasis and dipylidiasis, placing
pressure on health systems and draining
the economy of a country. It has been
calculated that in the USA in 1985, human
salmonellosis alone caused financial loss
of some 3 billion dollars. This estimate did
not include expenses ensuing from the
sequelae of salmonellosis, or from the
legal action undertaken by victims of food
poisoning
1
.
In any given region or society, the
particular disease agents, the frequency
with which zoonotic transmission occurs
and the resulting public health impact
reflect the nature of the local human–
animal relationships as well as climatic
conditions and socioeconomic circum
-
stances.
Table 1 provides a list of what have pre
-
viously been considered the most impor
-
tant zoonotic conditions found in South
Africa
1,11
. It illustrates that many zoonotic
diseases are known to occur in South
Africaandshows that mostof the diseases
can be associated with farm animals or a
rural environment. The question there
-
fore arises: what are the risks to South
African veterinarians, and the general
public who routinely come into contact
with these animals?
Given that many emerging diseases
come from animals and that the human
population in South Africa is increasingly
immunocompromised as a result of ac
-
quired immune deficiency syndrome
(AIDS), it is concomitantly of importance
to consider the role of zoonotic diseases.
This survey aims at assessing the risks of
acquiring zoonotic diseases bySouth Afri
-
can veterinarians.
MATERIALS AND METHODS
The survey included all veterinarians
working at the Faculty of Veterinary
Science, University of Pretoria, Pretoria,
South Africa, in December 2001. They
comprised the single largest group of
employed veterinarians, from the various
disciplines in the profession, located at
one place in South Africa and could there-
fore be relatively easily interviewed.
During the interview-based, question-
naire survey, each veterinarian was per-
sonally interviewed and answers to
questions recorded on a data capture
sheet. The information was entered into
Microsoft Access (Office 2000, Microsoft
Corporation, Redmond, USA) for colla
-
tion and analysed using EpiInfo 2002
(Centers for Disease Control and Preven
-
tion, US Department of Human and
Health Sciences, USA).
The questionnaire required responses
to the following:
1.
Surname.
2. Initial.
3. Date of birth.
4. Sex.
5. Year of graduation as a veterinarian.
6. Species that you have most predominantly
worked with during your career choose
one: small animal, large animal, mixed,
other (please specify).
a
Section of Epidemiology, Department of Production
Animal Studies,Faculty of Veterinary Science, University
of Pretoria, Private Bag X04, Onderstepoort, 0110 South
Africa. E-mail: bgummow@op.up.ac.za
Received: February 2003. Accepted: July 2003.
ABSTRACT
A survey of 88 veterinarians employed at the Faculty of Veterinary Science, University of
Pretoria, South Africa, was carried out to investigate the occurrence of zoonotic diseases
among South African veterinarians. The survey found that 63.6 % of veterinarians inter
-
viewed had suffered from a zoonotic disease. Veterinarians predominantly involved in
farm animal practice were 3 times more likely to have contracted a zoonotic disease than
those working in other veterinary fields. Fifty-six percent of disease incidents were initially
diagnosed by the veterinarians themselves. Fifty-three percent of incidents required treat
-
ment by a medical practitioner, but the majority (61 %) of incidents did not require absence
from work. The incidence density rate for contracting a zoonotic disease was 0.06 per per
-
son year of exposure. Kaplan-Meier survival analysis estimated that the probability of hav
-
ing contracted a zoonotic disease was 50 % after 11 years in practice. The risk of contracting
azoonoticdisease appeared tobehigher early inpractice. The mostcommonmode of trans
-
mission was by direct contact. Approximately 46 % of South Africans still live in rural areas
andregularlycome into close contactwithfarmanimals. The implications ofthisin the light
of this survey’s results are discussed.
Key words: prevalence, South Africa, survey, veterinarians, zoonoses.
Gummow B A survey of zoonotic diseases contracted by South African veterinarians.
Journal of the South African Veterinary Association (2003) 73(3): 72–76 (En.). Section of Epidemi-
ology, Department of Production Animal Studies, Faculty of Veterinary Science, University
of Pretoria, Private Bag X04, Onderstepoort, 0110 South Africa.
Table 1: Zoonoses that have traditionally been regarded as important in South Africa.
Viral diseases Bacterial diseases Helminth infections Other
Rift Valley fever Anthrax Toxoplasmosis Psittacosis
Rabies Brucellosis Taeniasis S A tick bite fever
Congo haemorrhagic fever Leptospirosis Dipylidiasis Ringworm
Salmonellosis Hydatidosis Cat scratch fever
Campylobacteriosis Larval migrans
Erysipeloid
7. Has your career predominantly involved,
fieldwork, clinic/hospital work, both, other
(please specify)?
8. What zoonoses have you contracted during
your life? Please refer to attached document
for a list that may help you remember.
9. For EACH zoonosis please state:
a. Whether it was contracted by: direct con
-
tact (e.g. post mortem), vector (e.g. tick),
other means (specify).
b. Whether the diagnosis was made by:
yourself, a general practitioner or a spe
-
cialist (specify).
c. What year did you suffer from the zoo-
noses?
d.What province were you in when you
contracted the zoonoses?
e. How many days sick leave did you have
to take?
f. Did you require treatment from a medical
practitioner?
g. What was the treatment?
h.What type of work were you doing at the
time of contracting it: large animal, small
animal, mixed, research, recreation, other
(specify).
i. Any other facts that you may think will
help with the survey.
Question 8 referred to a list of 70 of the
more commonly found zoonotic diseases
as defined by the WHO. This was not an
all-inclusive list of zoonotic diseases and
was aimed at jogging an interviewee’s
memory as to what diseases he/she may
have contracted.
RESULTS
In total, 88 veterinarians were inter
-
viewed. Fifty-six (63.6 %) of the veterinar
-
ians had suffered from one or more
zoonoses. Amongst these veterinarians,
93 incidents of zoonotic disease (Table 2)
were reported, ranging from 1 to 6
incidents of disease per veterinarian, with
a mean of 1.66 incidents. Thirty-two
(36.4 %) veterinarians could not recall
ever having contracted a zoonotic disease
(Table 2). Recurrent infections of the same
disease were not considered.
Assuming the sample was representa
-
tive of the population of South African
veterinarians, then the true prevalence of
zoonotic disease can be simulated stochas
-
tically using a beta distribution function
and Latin hypercube sampling
12
. Fig. 1
shows the cumulative distribution curve
fortheestimatedtrue prevalence of South
African veterinarians that have experi
-
enced a zoonotic disease. Given the sam
-
ple size, the true prevalence could range
from a minimum of 45 % to a maximum of
82 %.
Table 3 shows the percentage of inci-
dents of disease according to the occupa-
tion category of veterinarians at the time
when they contracted the zoonoses.
The category ‘Farm animal practice’
included mainly incidents of disease
while working with bovines (31 inci-
dents) and single incidents while pre-
dominantly working with equines,
porcines and poultry. Specialist veterinar-
ians that contracted zoonoses were exclu
-
sively pathologists. Other specialist
categories considered were anatomy,
anaesthesiology, dentistry, helminthol
-
ogy, exotic animals, surgery and pharma
-
cology, but none of these veterinarians
had contracted zoonoses. The odds ratio
of a veterinarian involved in farm animal
practice of contracting a zoonotic disease
was 3.11 (1.04 < OR < 11.23) compared
with all other categories and 3.58 (0.93 <
OR <15.13) compared only with small
animal practitioners.
In 55 % of the93 incidents of disease,the
initial diagnoses were made by the veteri
-
narian themselves. Thirty-two percent
were diagnosed by a general medical
practitioner and 10 % were diagnosed by
a specialist physician. The remainder
were 3 rabies exposure cases.
Fifty-three percent of incidents (n = 49)
required treatment by a medical practitio
-
ner.
Table 4 shows the number of days
sick leave required for each incident of
disease, grouped into intervals.
The majority of incidents (61 %) did not
require an absence from work. Forty-four
percent (n = 24) of these incidents were
cases of ringworm. Of those diseases
requiring up to 7 days sick leave, tick bite
fever made up the bulk of cases. Diseases
that consistently required a long absence
from work were notably Rift Valley fever
(RVF) and brucellosis. The days sick leave
for 4 incidents are not shown because of
uncertainty by the interviewee about the
time spent on sick leave or because there
were several bouts of the disease.
Table 5 shows the percentage of veteri
-
narians, grouped by year of graduation,
that reported having contracted zoono
-
ses. With the exception of the 1960–1969
period, the table confirms what is ex
-
pected, that the longer a veterinarian has
been in practice the greater are his/her
chancesofcontractingazoonoticdisease.
From the records of 47 of the 56 veteri
-
narians that had had zoonoses, it was
possible to calculate the number of years
from graduation until contracting their
1st zoonotic disease. The modal number
0038-2809 Jl S.Afr.vet.Ass. (2003) 74(3): 72–76 73
Table 2: Zoonotic diseases contracted by
the veterinarians interviewed and the num
-
ber of incidents reported for each disease.
Zoonoses Number
None 32
Ringworm 24
Tick bite fever 21
Rift Valley fever 8
Brucellosis 7
Cutaneous larval migrans 4
Sarcoptes
4
Malaria 3
Q-fever (
Coxiella burnetti
)3
Rabies exposure 3
Psittacosis 2
Shistosoma
2
Taeniasis 2
Candida
1
Corynebacteria 1
Erysipelothrix
1
Orf 1
Pseudocowpox 1
Rabies 1
Salmonella
1
Shigella
1
Toxoplasma
1
West Nile fever 1
Fig. 1: Cumulative distribution curve showing the expected true prevalence of South
African veterinarians that have contracted a zoonotic disease.
Table 3: Percentage of incidents of disease
per occupation category at the time of
contracting the disease.
Occupation category % of incidents
Farm animal practice 37
Small animal practice 20
Mixed animal practice 14
Specialist veterinarian 7.5
Research veterinarian 6.5
Other 15
of years to contracting the 1st zoonotic
disease was 1 year with an average of 6.5
years (SD = 7.5). It was also possible to
calculate an incidence density rate using
person years in practice as the
denominator
10
. There were 47 veterinari-
ans that contracted a zoonotic disease
over 833 person years at risk, thus giving
an incident density rate of 0.06 per person
year of exposure (i.e. a South African
veterinarian has on average a 6 % chance
of contracting a zoonoses for every year
of exposure). Another method used to
estimate risk to veterinarians was by
means of a Kaplan-Meier survival analy
-
sis. Survival analysis is the study of the
distribution of lifetimes. That is, the study
of the elapsed time between initiating an
event (in this case when the veterinarian
graduated) and a terminal event (in this
case when a veterinarian 1st contracted a
zoonotic disease). Table 6 shows the re
-
sults of a linear (Greenwood) Kaplan-
Meier survival analysis expressed in
quantiles of survival time, where survival
refers to the chances of not contracting a
zoonotic disease and failure refers to the
chances of contracting at least 1 zoonotic
disease.
The median point (0.5) is at 11 years, i.e.
half the veterinarians had contracted a
zoonotic disease within at least 11 years of
practice. Figure 2 shows the Kaplan-
Meier survival plot as well as the point
-
wise confidence intervals. In the plot,
time refers to years and survival to the
proportion of veterinarians not having
contracted a zoonotic disease. The shape
of the plot shows that a veterinarian has a
much higher chance of contracting a
zoonotic disease early in their time in
practice and that this risk levels off if they
have not yet contracted a zoonotic dis-
ease. It is important to note that the plot
74 0038-2809 Tydskr.S.Afr.vet.Ver. (2003) 74(3): 72–76
Table 4: Days absent from work per zoonoses.
Zoonoses No sick leave 1–7 days 6–14 days >14 days
Brucellosis 3 0 0 3
Candida
1000
Cutaneous larval migrans 4 0 0 0
Corynebacteria 1 0 0 0
Erysipelothrix 1 0 0 0
Malaria 0 1 0 1
Orf 0 1 0 0
Pseudocowpox 0 1 0 0
Psittacosis 1 0 1 0
Q-fever 0 2 1 0
Rabies 0 0 1 0
Rabies exposure 3 0 0 0
Ringworm 24 0 0 0
Rift Valley fever 1 3 3 1
Sarcoptes
3100
Shigella
0010
Schistosoma
1100
Taeniasis
2000
Tick bite fever 8 11 1 0
Toxoplasma
0001
West Nile fever 1 0 0 0
Total 54 21 6
Percentage 61 24 9 7
Table 5: Percentage of veterinarians according to graduation date that reported having contracted a zoonotic disease.
<1960 1960–1969 1970–979 1980–1989 1990–1999 >2000 Total
No zoonoses 1 5 3 10 12 1 32
Zoonoses 5 3 17 14 17 0 56
Total 6 8 20 24 29 1 88
% that contracted a zoonoses 83 37 85 58 59 0 64
Table 6: Kaplan-Meier survival analysis results expressed as quantiles.
Proportion surviving Proportion failing Survival time (years) Lower 95 % CL* Upper 95 % CL
survival time survival time
0.95 0.05 1 1
0.9 0.1 1 1
0.85 0.15 1 1 2
0.8 0.2 2 1 2
0.75 0.25 3 1 3
0.7 0.3 3 2 5
0.65 0.35 4 3 8
0.6 0.4 5 3 10
0.55 0.45 8 4 11
0.5 0.5 11 5 18
0.45 0.55 12 7 22
0.4 0.6 18 10 22
0.35 0.65 28 11 28
0.3 0.7 28 15 28
0.25 0.75 22 28
0.2 0.8 28 28
0.15 0.85 28 28
0.1 0.9 28
0.05 0.95 28
*CL = confidence limit
does not take into account multiple or re
-
peated infections.
Of the 88 veterinarians interviewed, 19
were female and 69 male. Twelve (63 %)
females and forty-four (63.8 %) males
contracted zoonoses. No difference could
therefore be shown between male and
female veterinarians in terms of the riskof
contracting a zoonotic disease.
Table 7 shows where each incident of
zoonotic disease was contracted. The
majorityof incidents occurredinGauteng
but this, in hindsight, may be due to
the biased nature of the survey, which
concentrated on veterinarians that proba
-
bly worked predominantly in Gauteng
while in practice.
Table 8 shows the mode of transmission
of each disease incident. Included under
direct transmission were diseases con
-
tracted while conducting necropsies.
Direct contact was the most frequent
mode of transmission.
DISCUSSION
The survey carried out at the Faculty of
VeterinaryScience, University ofPretoria,
in 2001, showed that a high proportion of
veterinarians (45–82 %) had contracted
zoonotic diseases and that many of the
zoonotic diseases contracted by veteri-
narians had not immediately been diag
-
nosed by general practitioners and often
had to be diagnosed with the assistance of
the veterinarian. This highlights the fact
that many zoonotic conditions are diffi
-
cult to diagnose clinically and are proba
-
bly frequently misdiagnosed or missed.
For example, brucellosis, leptospirosis,
tick-bite fever, Q-fever and Rift Valley
fever can all present with similar clinical
signs in man in the early stages. In areas
where malaria is endemic, they can easily
be misdiagnosed as malaria cases if no
diagnostic confirmation tests are carried
out.
A study of medical curricula in South
Africa shows a deficiency of training at an
undergraduate level in recognising
zoonotic conditions. Another compound
-
ing factor is the inexperience of the junior
doctors working unsupervised in many
district hospitals in South Africa. Coupled
to this are limited laboratory facilities and
a lack of funds to carry out comprehensive
diagnostic procedures (D A Cameron,
Department of Family Medicine, Univer
-
sity of Pretoria, pers. comm., 2002). It is
thus conceivable that a large number of
zoonotic conditions are currently mis
-
diagnosed or go undiagnosed in South
Africa.
The survey showed that veterinarians
working with farm animals are at higher
risk of contracting zoonotic diseases than
those working with small animals. It also
showed that direct contact is still the most
prevalentmeans of contracting a zoonotic
disease. Personal hygiene and protective
clothing, therefore, are probably the most
important ways of preventing transmis
-
sion of zoonotic diseases.
The survey illustrated that the longer
veterinarians have been in practice, the
greater their chances are of contracting a
zoonotic disease. It also showed that a
veterinarian is more likely to contract a
zoonotic disease early on in his/her time
in practice. A similar trend is likely to
manifestintherural areas of South Africa.
South African demographic data show
that 46.3 % of the population still lives in
rural areas, and can be expected to regu
-
larly come into close contact with farm
animals and their parasites
9
. In many
cases, they share the same water sources
and habitat, making transmission of dis
-
eases between animals and man very
likely. Compounding this are the poor
socioeconomic conditions under which
many South Africans live. These result in
malnutrition and poor sanitation within
these communities, providing an ideal
environment for the transmission and
maintenance of infectious diseases.
In a recent study by the South African
Medical Research Council it was etimated
that 40 % of adult (15–49 years of age)
deaths that occurred in 2000 in South
Africa were due to HIV/AIDS
4
. Histori
-
cally, it has been this component of soci
-
ety that has been at lowest risk of con-
tracting zoonotic diseases because many
zoonotic conditions only manifest in
immunodeficient individuals, such as
children and the very old. Conditions
such as ringworm,Q-fever,tick-bite fever,
cutaneous-anthrax, cat scratch disease
and toxoplasmosis, to name but a few,
that many adults would shrug off, as
evidenced by the relatively few days
sick leave taken by veterinarians in this
study, take on a new meaning when indi
-
viduals become immunocompromised.
According to Grant and Olsen
6
, animal-
associated pathogens of concern to
immunocompromised persons in the
USA include Toxoplasma, Cryptosporidium,
Salmonella, Campylobacter, Giardia lamblia,
Rhodococcus equi, Bartonella, Mycobacte
-
rium, Bordetella bronchiseptica, Chlamydia
psittaci and zoophilic dermatophytes.
From the present survey it also became
apparent that in South Africa this list is
probably longer and the consequences
0038-2809 Jl S.Afr.vet.Ass. (2003) 74(3): 72–76 75
Fig. 2: Kaplan-Meier survival plot for the time (years) between graduation and contracting a
zoonotic disease.
Table 7: Location where each incident of
zoonotic disease was contracted.
Country/region Frequency
Gauteng 42
Uncertain 10
KwaZulu-Natal 9
Mpumalanga 6
North West Province 6
Northern Province 5
Eastern Cape 3
Free State 3
Northern Cape 2
Western Cape 1
Mozambique 1
Nigeria 1
Ohio, USA 1
Swaziland 1
UK 1
Zimbabwe 1
Total 93
Table 8: Mode of transmission of each
disease incident.
Mode of transmission Number
Direct contact 58
Vector 24
Uncertain 7
Ingestion 4
76 0038-2809 Tydskr.S.Afr.vet.Ver. (2003) 74(3): 72–76
more life-threatening. Certainly, some of
the conditions found in the survey, such
as malaria, tick bite fever, brucellosis,
Q-fever and Rift Valley fever, need to be
included in a South African list.
While some work has been done on the
role of zoonotic diseases in immuno-com
-
promised persons, most, if not all,
emanated from first world countries.
Earlier studies concluded that the risk of
zoonotic transmission to HIV patients
was small and that the benefits of animal
companionship outweigh the risks to
HIV patients
5
. This perception appears to
be changing and, more recently, Grant
and Olsen
6
suggested that with the ex
-
ception of Bartonella henselae and zoophi
-
lic dermatophytes, infections in humans
are more commonly acquired from
sources other than pets, and the infec
-
tious disease risk fromowning pets is con
-
sidered low. Nevertheless, HIV-infected
persons may still be advised not to own
pets’. While this may be so in developed
countries, the WHO in one of its latest
reports stated that ‘Infectious diseases
will remain the major causes of mortality
in most developing countries, with
HIV/AIDS and opportunistic infections
(including zoonoses) being especially
important’
13
. The high proportion of
veterinariansin this surveythathave con-
tracted zoonotic diseases supports this
statement.
Macpherson et al.
7
reported that ‘The
average prevalence of Cryptosporidiosis
parvum in patients with HIV has been re-
ported to be 27 % in developing countries
and 12 % in industrialised countries. The
life-threatening potential of C. parvum
infections in immunocompromised and
immunosuppressed individuals has
greatly enhanced the importance of
cryptosporidiosis asa global publichealth
problem’. Referring to toxoplasmosis
they go on to state that a risk group of
special interest has emerged, that of
non-immune HIV positive pregnant
women’. Toxoplasmosisin HIV patients is
reportedly of long-duration and may be
followed by death. Recent studies have
also shown that T. gondii is the most com
-
mon cerebral opportunistic infection of
patients with AIDS
3
. More than 90 % of
the estimated 36 million people with HIV/
AIDS live in developing countries
13
.In
Africa, the role of veterinarians in control
-
ling these diseases is thus becoming in
-
creasingly important. Coupled to this is
the responsibility of veterinarians to keep
abreast of new information on emerging
zoonotic conditions and to keep the
publiceducatedastotheirconsequences.
Given that a diversity of zoonotic condi
-
tions have been reproted in South Africa,
that a large segment of the population is
immunocompromised and that they are
likely to come into contact with animals
on a regular basis under poor socioecono
-
mic conditions, one can justifiably put
forward the hypothesisthat the incidence
and severity of certain zoonotic condi-
tions are likely to increase at a similar rate
to that of the HIV/AIDS epidemic, thus
compounding an already serious situa-
tion.
ACKNOWLEDGEMENTS
The author wishes to thank David Brad-
bury, a final-year student at the Faculty of
Veterinary Science at the time of the
survey, for assisting him in interviewing
veterinarians, and David Cameron, a
medical practitioner in the Department of
Family Medicine, University of Pretoria,
for providing insights into the AIDS situa
-
tion in South Africa.
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Series 907. WHO, Geneva
... En las encuestas sobre salud laboral publicadas (tabla 1), la frecuencia de profesionales veterinarios que comunican haber padecido al menos una zoonosis oscila entre el 4% y el 64,3%. El rango de incidentes zoonósicos referido por los afectados varía entre 1 y 6, con una media de 1,66 incidentes por profesional (18) . De forma general, la mayoría de profesionales afectados (65,7% (13) -83,6% (10) ) comunican haber padecido solo una zoonosis y con menor frecuencia se informa haber padecido 2 (23%), 3 (6,9%) y 4 o más zoonosis (3.9%) (13) . ...
... Tuberculosis (2). Leptospirosis (2) García (2006) (14) Países (18) a: número de profesionales encuestados en el estudio; b : base de datos que incluye 27.500 profesionales veterinarios y sus equipos cubiertos por la Seguridad Social alemana; c : sobre el total de enfermedades profesionales solicitadas; d : casos de zoonosis reconocidos como enfermedad profesional; e,f : casos de zoonosis confirmados y sospechosos adquiridos en el ámbito laboral, respectivamente; g : administración de terapia post-exposición sin diagnóstico de rabia; h : porcentaje de casos de enfermedad por categoría de ocupación. ...
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The veterinary profession implies a greater risk of infection by zoonotic pathogens than the overall population. The aim of the present work was to evaluate the impact of zoonoses on the occupational health of veterinarians reviewing the published surveys addressing this subject. Following these inquiries, between 4% and 64.3% of the surveyed professionals acknowledge to have suffered at least one zoonotic disease, and dermatophytosis is the most frequently described zoonosis. In addition, from a qualitative point of view, it is necessary to highlight the occurrence of different diseases of important clinical seriousness and the existence of infections by antimicrobial-resistant pathogens. Due to the absence of updated studies in Spain, the present work reflects on the need to recognize the health determinants associated to the veterinary profession within the characteristics of our labour market. The available data suggest that the occurrence of zoonoses as occupational diseases is underestimated in Spain. Therefore, performing surveys on occupational health, documenting and publishing cases and reviewing the risks and the impact of zoonotic diseases on the veterinary profession would contribute to the description and notification of such diseases on behalf of the healthcare administration and would also become an essential tool in occupational risk prevention.
... Accidental exposure to RB51 through needlestick injury has been implicated as one of the main causes of brucellosis in veterinarians and their assistants [42,43]. Occupational risk to abattoir workers [33] and veterinarians has been well documented [28,[44][45][46][47][48]. In this study, all the veterinary officials that tested seropositive were para-veterinarians, also known as animal health technicians, employed by the Government to perform selected veterinary services. ...
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Brucellosis in humans is under-detected and underreported in sub-Saharan Africa. Risk factors associated with Brucella infection and health seeking behaviour in response to brucellosis-like symptoms, amongst cattle farm workers and veterinary officials in South Africa, are unknown. Farm workers and veterinary officials (N = 230) were screened for brucellosis using commercial Rose Bengal Test (RBT®), IgM Enzyme-linked Immunoassay (ELISA)®, IgG ELISA® and the BrucellaCapt® test. Knowledge of brucellosis and risk factors for exposure to Brucella were also investigated. Seroprevalence varied according to test used: 10.1% (RBT®), 20.9% (IgG ELISA®) and 6.5% (BrucellaCapt®). Only 22.2% (6/27) of veterinary officials opt to visit a clinic, doctor, or hospital in response to self-experienced brucellosis-like symptoms, compared to 74.9% (152/203) of farm workers (p < 0.001). Of the BrucellaCapt® seropositive participants, 53% (7/15) did not visit a clinic in response to brucellosis-like symptoms. Weak evidence of an association between the handling of afterbirth or placenta and infection of a short evolution (RBT®, IgM ELISA® and IgG ELISA® seropositive) was found (OR = 8.9, 95% CI: 1.0–81.1, p = 0.052), and strong evidence of an association between this outcome and the slaughter of cattle (OR = 5.3, 95% CI: 1.4–19.6, p = 0.013). There was strong evidence of a positive association between inactive/resolved infection and veterinary officials vs. farm workers exposed to seropositive herds (OR = 7.0, 95% CI: 2.4–20.2, p < 0.001), with a simultaneous negative association with the handling of afterbirth or placenta (OR = 3.9, 95% CI: 1.3–11.3, p = 0.012). Findings suggest a proportion of undetected clinical cases of brucellosis amongst workers on cattle farms in Gauteng.
... In nature, vertebrates such as cattle are believed to be bacteremic for a very short period of time and hence considered as reservoirs of infection [17] resulting in classification of ATBF as zoonotic. A majority of population in South Africa live in rural areas and comprise of resource-poor livestock farmers who are regularly in contact with their livestock and thereby exposed to parasites and tick bites making transmission of zoonotic parasites possible [18]. ...
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Background African tick bite fever (ATBF) caused by Rickettsia africae and transmitted by Amblyomma spp. ticks is one of the zoonotic tick-borne fevers from the spotted fever group (SFG) of rickettsiae, which is an emerging global health concern. There is paucity of information regarding the occurrence and awareness of the disease in endemic rural livestock farming communities living in livestock-wildlife interface areas in South Africa. Methods The purpose of the study was to assess the level of knowledge, attitudes and practices on ticks and ATBF infection from a community living in livestock-wildlife interface areas in South Africa. A focus group discussion (FGD) was carried out followed by verbal administration of a standardized semi-structured questionnaire a month later to 38 rural livestock farmers (23 from Caquba area and 15 from Lucingweni area where A. hebraeum was absent). An FGD was conducted in Caquba (situated at the livestock-wildlife interface where Amblyomma hebraeum was prevalent on cattle and infected with Rickettsia africae ) in the O.R. Tambo district of the Eastern Cape province of South Africa. Results Results from the FGD and questionnaire survey showed that participants from the two rural communities were not aware of ATBF and were not aware that ticks are vectors of the disease. Respondents from Caquba reported of having frequent exposure to tick bites (91.3%, 21/23) specifically from the anthropophilic A. hebrauem which they were able to identify as Qwelagqibe in IsiXhosa (their vernacular). Thirteen out of 15 (86.7%) of respondents from Lucingweni reported that they had never been bitten by ticks, which corresponded with the absence of A. hebraeum from their locality as evidenced from results of a concurrent study on prevalence of ticks on livestock in the area. Both communities confirmed to being “very concerned” of tick bites and we presume this was more related to the localized wounds from the bites than to the diseases transmitted by the ticks. Conclusions We recommend future studies encompassing seroprevalence of ATBF in Caquba and other communities at risk in South Africa including establishing surveillance systems to monitor the seasonal infection rates in ticks, cattle and humans.
... 17 Another study of veterinary staff at the South African veterinary faculty found >60% had evidence of a previous zoonotic infection. 22 Despite these risks, medical professionals often have low levels of knowledge about zoonoses, with frequent misdiagnoses or underdiagnoses. 23 Wildlife is seen as a source of emerging diseases for humans. ...
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Background: Zoonoses pose major threats to the health of humans, domestic animals and wildlife, as seen in the COVID-19 pandemic. Zoonoses are the commonest source of emerging human infections and inter-species transmission is facilitated by anthropogenic factors such as encroachment and destruction of wilderness areas, wildlife trafficking and climate change. South Africa was selected for a 'One Health' study to identify research priorities for control of zoonoses due to its complex disease burden and an overstretched health system. Methods: A multidisciplinary group of 18 experts identified priority zoonotic diseases, knowledge gaps and proposed research priorities for the next 5 y. Each priority was scored using predefined criteria by another group of five experts and then weighted by a reference group (n=28) and the 18 experts. Results: Seventeen diseases were mentioned with the top five being rabies (14/18), TB (13/18), brucellosis (11/18), Rift Valley fever (9/11) and cysticercosis (6/18). In total, 97 specific research priorities were listed, with the majority on basic epidemiological research (n=57), such as measuring the burden of various zoonoses (n=24), followed by 20 on development of new interventions. The highest research priority score was for improving existing interventions (0.77/1.0), followed by health policy and systems research (0.72/1.0). Conclusion: Future zoonotic research should improve understanding of zoonotic burden and risk factors and new interventions in public health. People with limited rural services, immunocompromised, in informal settlements and high-risk occupations, should be the highest research priority.
... Skin fungal infections can become severe, remain a great threat to people, and are more likely to cause death if they are either not treated or poorly controlled. 4 In South Africa, the prevalence of dermatophyte mycosis has also increased due to the increase in immunosuppressed human immunodeficiency virus patients. This has prompted the search for plant sources of antimicrobial agents. ...
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Dermatophytosis is a fungal infection of the skin caused by a group of pathogenic fungi known as dermatophytes. Therefore, we investigated those medicinal plants that were being used by local people and traditional healers to treat skin infections in the Mopani District, Limpopo Province. A survey was conducted through the use of a semistructured program to gather information on the common names, plant parts used, methods of preparation, and administration of the medicine. Findings of the survey revealed that over 30 plant species were used for the treatment of skin infections in the area. The most common local mode of medicinal preparation to treat skin was decoction (37%), followed by paste (21%), infusion (19%), poultice (9%), smoke (7%), maceration (5%), and steam (2%). Of the species, only 12 ( Ficus sur L., Peltophorum africanum Sond., Vangueria infausta Burch. subsp. infausta, Diospyros mespilliformis Hochst. ex. A. DC., Ziziphus mucronata Willd. subsp. mucronata, Euclea divinorum Hiern, Ximenia caffra Sond., Dombeya rotundifolia Hochst., Ficus sycomorus L., Sideroxylon inerme L. subsp inerme, Parinari curattellifolia Planch. ex Benth., and Maytenus undata (Thunb.) Blakelock) were selected based on literature and ethnobotanical information. We further investigated the antifungal activity of acetone and aqueous extracts of the above mentioned selected plant species using serial dilution assay against Trichophyton rubrum, Microsporum canis, and Candida albicans. All plant extracts were active against the tested microorganisms with minimum inhibitory concentration (MIC) values ranging between 0.02 mg/mL and 1.25 mg/mL. In the bioautography assay, more active compounds were visible in acetone and water extracts of E. divinorum. No active compounds were observed in some plant extracts with excellent antifungal activity, as shown in the microdilution assay. Findings, in general, suggest that the identified plant species, especially those with extracts showing relatively low MIC values, are playing a big role in treating skin infections in Mopani District.
... A University of Pretoria-based study revealed that veterinarians working at the university had contracted virus zoonotic diseases, including rabies virus, RVFV, and WNV diseases, until the year 2001 [276]. ...
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Emerging and re-emerging viral diseases are of great public health concern. The recent emergence of Severe Acute Respiratory Syndrome (SARS) related coronavirus (SARS-CoV-2) in December 2019 in China, which causes COVID-19 disease in humans, and its current spread to several countries, leading to the first pandemic in history to be caused by a coronavirus, highlights the significance of zoonotic viral diseases. Rift Valley fever, rabies, West Nile, chikungunya, dengue, yellow fever, Crimean-Congo hemorrhagic fever, Ebola, and influenza viruses among many other viruses have been reported from different African countries. The paucity of information, lack of knowledge, limited resources, and climate change, coupled with cultural traditions make the African continent a hotspot for vector-borne and zoonotic viral diseases, which may spread globally. Currently, there is no information available on the status of virus diseases in Africa. This systematic review highlights the available information about viral diseases, including zoonotic and vector-borne diseases, reported in Africa. The findings will help us understand the trend of emerging and re-emerging virus diseases within the African continent. The findings recommend active surveillance of viral diseases and strict implementation of One Health measures in Africa to improve human public health and reduce the possibility of potential pandemics due to zoonotic viruses.
... b) Al igual que en estudios anteriores, los diagnósticos fueron más frecuentes en los primeros años de profesión (Gummow, 2003;Imoberdorf et al., 2017). La mitad de los veterinarios infectados había sido diagnosticada con brucelosis dentro de los 6 años de práctica. ...
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The aim of this work was to evaluate the effect of the graduation moment, years of graduation and region (within the Province of Santa Fe) on the risk of brucellosis in veterinarians working in general practices with bovines. Data was collected by a survey using a structured questionnaire which was answered anonymously by 464 professionals. Two studies were conducted: 1) the cohorts of veterinarians graduated from one to 10, 11 to 20 and more than 20 years prior to the survey were compared, considering only the new cases of brucellosis recorded during those periods; 2) the regions where the veterinarians performed their practice, defined according to the Plan Superador de Brucelosis Bovina from SENASA, were compared. Statistical analysis included the Relative Risk estimation (RR) and logistic regression. The cumulative incidence rate (CIR) of brucellosis was 25.6%, with a higher frequency at the beginning of the professional activity and in veterinarians graduated more time ago (P<0.001). The veterinarians who worked in the Center-South Region had a CIR of brucellosis in their first 10 years of work of 22.9%, significantly higher than their colleagues who practiced in the North region (CIR = 11.6%) (P=0.004). The tendency to concentrate the cases in the first years of professional activity was observed in both regions, although with greater intensity in the Center-South Region (P<0.001). We concluded that the region of professional practice and the temporary variables (time of graduation and years of graduation) are undoubtedly linked to each other.
... Pseudocowpox virus, the other parapoxvirus able to infect humans, has also been identified as a zoonosis in South African veterinarians [64]. However, both orf and pseudocowpox infections are neglected zoonoses, and are likely to be under-recognised by medical practitioners. ...
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Background Veterinarians may encounter a variety of zoonotic pathogens in their work. Methods We conducted 2 cross-sectional questionnaire studies among veterinarians in Finland. Participants were recruited during 2 Annual Veterinary Congresses. In 2009, 306 veterinarians participated in an extensive questionnaire study, and in 2016, 262 veterinarians participated in a more focused study that included 2 same questions. Results In 2009, the majority (90.9%) of the participating veterinarians reported having been occupationally exposed to zoonotic pathogens. Zoonotic infections (15.0%), needle stick incidents (78.8%), bites (85.0%), as well as infected skin lesions (24.2%) were reported. In 2009, 8.2% of the participants fully agreed with the statement ‘I have good knowledge of zoonoses and their prevention’; in 2016, the proportion was 10.3%. The reported use of protective practices and personal protective equipment in connection with specific veterinary procedures indicated that there was room for improvement, particularly in protection from pathogens that are transmissible via inhalation and mucous membranes. Conclusion The results confirm that veterinarians are commonly occupationally exposed to zoonotic pathogens. Education should aim to improve and maintain the knowledge of zoonoses and their prevention. Use of protective practices should be advocated.
Article
Veterinarians play a crucial role in zoonotic disease detection in animals and prevention of disease transmission; reporting these zoonoses to public health officials is an important first step to protect human and animal health. Evidence suggests veterinarians and their staff are at higher risk for exposure to zoonoses because of possible interactions with infected animals. We examined the knowledge, attitudes, and practices of veterinarians regarding zoonotic disease reporting to public health agencies and associated infection prevention (IP) practices such as personal protective equipment (PPE) use, and the need for targeted education and outreach for veterinarians in Arizona. An online questionnaire was developed and distributed by email in September 2015 and was available through November 2015 to all 1,100 members of the Arizona Veterinary Medical Association. Chi-square and logistic regression analyses were performed. In total, 298 (27%) veterinarians from all 15 Arizona counties completed the survey; the majority (70%) were female, practiced small animal medicine (84%), and reported practicing veterinary medicine for ≥10 years (75%). Only 57% reported they knew when to report a suspected zoonotic disease and 60% reported they knew how to make that type of report. The majority said they would report rabies (97%), plague (96%), and highly pathogenic avian influenza (91%) to a state agency. Most respondents reported using PPE (e.g., masks, face shields, and gloves) when performing a surgical procedure (96%) or necropsy (94%), although fewer reported using PPE for handling clinically ill animals (37%) or healthy animals (17%). Approximately 70% reported always using PPE when in contact with animal birthing fluids, urine, or feces, and 47% for contact with animal blood, saliva, or other body fluids. Veterinarians who agreed that they knew the appropriate actions to protect themselves from zoonotic disease exposures were more likely to report always washing their hands before eating or drinking at work (OR = 3.81, 95% confidence interval (CI) [1.97-7.35], P < 0.01). Responses for when to make a report and how to report were not significantly different by gender, years of practice, or holding additional degrees, but did differ by practice type, age, and number of veterinarians in the practice. Small animal veterinarians were less likely to report knowing when to make a report compared to other veterinarians (P < 0.01). Respondents demonstrated suboptimal zoonotic disease reporting and IP practices, including PPE use. Public health agencies should improve outreach and education to veterinarians to facilitate better zoonotic disease prevention practices and reporting.
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We surveyed physicians and veterinarians in Wisconsin about the risk for and prevention of zoonotic diseases in immunocompromised persons. We found that physicians and veterinarians hold significantly different views about the risks posed by certain infectious agents and species of animals and communicate very little about zoonotic issues; moreover, physicians believe that veterinarians should be involved in many aspects of zoonotic disease prevention, including patient education.
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Estimates suggest that almost half of the population of the world is affected by water-borne and food-borne infections. Parasitic food-borne and water-borne zoonoses contribute to this statistic by inflicting a heavy toll on human health and causing serious direct and indirect losses to the agricultural industry. The inability of non-industrialised countries to keep pace with population growth, migration from rural to urban areas and the demand for clean, safe drinking water and proper sanitation means that water-borne zoonoses will continue to exact an increasing burden of ill health in these countries. The consumption of raw or undercooked meat, crustaceans, and fresh-water fish and vegetables facilitates transmission of large numbers of zoonotic infections. The burgeoning tourist industry, emigration and the importation of food from endemic regions has resulted in increasing diagnosis of these infections in non-endemic countries. The authors examine the epidemiology, medical and veterinary public health importance and recent developments in diagnosis, treatment and control of the most important parasitic food-borne and water-borne infections.
Article
A number of animal-associated infections occur in persons infected with the human immunodeficiency virus (HIV), including those due to Toxoplasma gondii, Cryptosporidium, Microsporida, Salmonella, Campylo-bacter, Giardia, Rhodococcus equi, Rochalimaea, and Listeria monocytogenes. Most of these infections, with the exception of those due to Rochalimaea, appear to be acquired by the immunosuppressed individual from sources other than exposure to animals. Drs. Glaser and colleagues review our current understanding of the role of exposure to animals, especially pets, in the natural history of these opportunistic infections. They suggest that the risk of zoonotic transmission is small and offer practical suggestions designed to reduce this low risk. They conclude that the benefits of animal companionship outweigh the risks to patients and that prohibition of pet ownership by individuals infected with HIV is not warranted.
Article
Many new, emerging and re-emerging diseases of humans are caused by pathogens which originate from animals or products of animal origin. A wide variety of animal species, both domestic and wild, act as reservoirs for these pathogens, which may be viruses, bacteria or parasites. Given the extensive distribution of the animal species affected, the effective surveillance, prevention and control of zoonotic diseases pose a significant challenge. The authors describe the direct and indirect implications for public health of emerging zoonoses. Direct implications are defined as the consequences for human health in terms of morbidity and mortality. Indirect implications are defined as the effect of the influence of emerging zoonotic disease on two groups of people, namely: health professionals and the general public. Professional assessment of the importance of these diseases influences public health practices and structures, the identification of themes for research and allocation of resources at both national and international levels. The perception of the general public regarding the risks involved considerably influences policy-making in the health field. Extensive outbreaks of zoonotic disease are not uncommon, especially as the disease is often not recognised as zoonotic at the outset and may spread undetected for some time. However, in many instances, the direct impact on health of these new, emerging or re-emerging zoonoses has been small compared to that of other infectious diseases affecting humans. To illustrate the tremendous indirect impact of emerging zoonotic diseases on public health policy and structures and on public perception of health risks, the authors provide a number of examples, including that of the Ebola virus, avian influenza, monkeypox and bovine spongiform encephalopathy. Recent epidemics of these diseases have served as a reminder of the existence of infectious diseases and of the capacity of these diseases to occur unexpectedly in new locations and animal species. The need for greater international co-operation, better local, regional and global networks for communicable disease surveillance and pandemic planning is also illustrated by these examples. These diseases have contributed to the definition of new paradigms, especially relating to food safety policies and more generally to the protection of public health. Finally, the examples described emphasise the importance of intersectorial collaboration for disease containment, and of independence of sectorial interests and transparency when managing certain health risks.
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