Seroprevalence of Q Fever in Cattle and Sheep in the East of Turkey
The present study was carried out to determine the seroprevalence of antibodies to C. burnetii in cattle and sheep in the east of Turkey. Serum samples collected randomly from 92 cattle and 92 sheep were examined by ELISA (Vircell-SL, Spain) to detect IgG antibodies against C. burnetii phase II antigen. Seropositivity was observed in 16.3% of the cattle and in 5.4% of the sheep. Coxiellosis has an important seropositivity in both cattle and sheep and it can cause serious health problem in humans living in Eastern Turkey.
Q fever (query fever), a zoonosis caused by obligate intracellular microorganism
Coxiella burnetii, is endemic throughout the world with the exception
of Antarctica and possibly New Zealand, occurring in diverse geographic regions
and climatic zones and infects arthropods, birds, pets, domestic and wild mammals,
as well as humans (Woldehiwet, 2004; Rodolakis,
Natural reservoirs are more than 40 species of ticks, which remain infected
life-long and which transmit C. burnetii transovarially and free-living
vertebrates. Tick feces may contain large amounts (up to 1010 infectious
units g-1) of C. burnetii (Norlander,
The main sources of environmental contamination and infection of humans are
parturient ruminants, dogs and cats infected with C. burnetii (Woldehiwet,
2004). The main route of C. burnetii infection is by inhalation of
contaminated aerosols or dusts containing the microorganism shed from infected
animals. The source of human infection is often unidentified, although sheep
and goats are more frequently involved in the disease cycle than other animal
species. Infected animals shed highly stable bacteria in urine, feces, milk
and through placental and birth fluids (Marrie, 2003).
Ccoxiella burnetii is very stable in the environment, resisting to elevated
temperature, desiccation, osmotic shock, ultra-violet light and disinfectants
(Arricau-Bouvery and Rodolakis, 2005). Oral transmission,
by ingestion of contaminated raw milk or dairy products could lead to seroconversion
in few cases to Q fever (Cutler et al., 2002;
McQuiston et al., 2002; Rodolakis,
Until recently, the agent has been regarded as economically unimportant for
domestic livestock. However, C. burnetii has been detected in a number
of cases of abortion in different parts of the world (Waldham
et al., 1978; Palmer et al., 1983;
Raju et al., 1988; Zeman
et al., 1989) including Turkey. As a result, the role of C. burnetii
in reproductive disorders of livestock has been questioned (Cetinkaya
et al., 2000). Although, the disease may cause agalactia (Kelly
et al., 1993) and infertility in addition to sporadic abortions in
heavily infected animals, it usually does not cause obvious clinical signs in
In animals, C. burnetii can induce pneumonia as well as abortion, stillbirth
and delivery of weak lambs, calves or kids, which are the most frequent clinical
signs of the disease. In the majority of the cases, abortion occurs at the end
of gestation without specific clinical signs until abortion is imminent, as
observed with brucellosis or chlamydiosis. Aborted fetuses appear normal but
infected placentas exhibit intercotyledonary fibrous thickening and discolored
exudates, which are not specific to Q fever. A severe inflammatory response
is observed in the myometrium and the stroma adjacent to the placentomal area
during gestation in goats (Abe et al., 2001).
From time to time clinical signs mentioned above have seen in the farm animals
in this region. Taken into consideration of these clinical signs, the possibility
of Q fever incidence in the region were therefore investigated serologically.
Isolation of C. burnetii is not performed for routine diagnosis in veterinary
medicine, because the cultivation of the agent is a laborious and hazardous
process (Rodolakis, 2006).
The diagnosis of Q fever remains difficult and epidemiological studies are often based only on serological investigations. These include Complement Fixation Test (CFT), Indirect Flourescent Antibody Test (IFAT), Capillary Agglutination (CA) test, indirect immunoflourescence assay (IFA), microagglutination test (MA), ELISA and PCR. Routine diagnosis of Q fever in aborted animals is usually established by examination of fixed impressions or smears prepared from the placenta stained by the Stamp, Gimenez or Machiavello methods, associated with serological tests. Because farm animals are the major source of the infection for people, it is important to determine the prevalence of coxiellosis in these species. The present study was carried out to determine the prevalence of coxiellosis in cattle and sheep in the eastern part of Turkey, using ELISA.
MATERIALS AND METHODS
A total of 184 blood samples (92 samples each of cattle and sheep) were
collected by a simple random sampling method from 16 herds and flocks as well,
representing 16 locations (Van, Baskale, Caldıran, Catak, Edremit, Ercis,
Gevas, Gürpınar, Muradiye, Ozalp, Bitlis, Adilcevaz, Ahlat, Tatvan,
Mus, Dogubayezıt) in the eastern part of Turkey (Fig. 1)
during 2006-2008 years. The herds and flocks were selected randomly.
||The sites of blood samples collection at the Eastern part of Turkey
No criteria such as size of herd or flock were used in the selection of the
herds and flocks. All animals were adult females and males. The 5-7 mL blood
were collected from flocks were selected randomly. No criteria such as size
of herd or flock were used in the selection of the jugular vein aseptically
using Vacutainer® tubes containing separator gel by qualified
personnel and kept on ice while being transferred to the Laboratory of Microbiology
and Clinical Microbiology, Medical Faculty at Yüzüncü Yil University,
where serum was separated by centrifugation (3000 rpm for 10 min) and stored
frozen at -20°C until required.
Serum samples were tested for C. burnetii antibodies using ELISA
test and Labsystems iEMS Reader MicroELISA system (Finland) was used. Commercial
ELISA kit (Vircell SL®, Spain) was used to detect IgG antibodies
against C. burnetii phase II antigen. The test was carried out according
to the instructions of the manufacturer. Four wells (two for the cut off serum
and one each for the negative and positive sera) in each ELISA plate were used
as control. The mean OD for the cutoff serum and antibody index was calculated
with the following formula:
Samples were interpreted as: samples with indexes <9.0 were considered as not having IgG antibodies; samples with equovocal results (AI = 9.0-11.0) being retested for confirmation and samples with indexes >11 were considered as having IgG antibodies against C. burnetii.
RESULTS AND DISCUSSION
Coxiella burnetii seropositivity reactions were obtained 10.9% of the sera tested from all animals (20 of 184). The highest percentage of positive animals was for cattle (%16.3) (Table 1).
The interest for Q fever is increasing worldwide as indicated by the rising
number of reviews published (Arricau Bouvery and Rodolakis,
2005) even in countries where its incidence is supposed to be very low.
Indeed, the disease is considered as a re-emerging zoonosis in many countries.
This could be due to the evolution of its epidemiology, or of the agent, which
could become more virulent, to modifications of its clinical signs, to an improvement
of the sensitivity of diagnostic tests, or because practitioners are better
informed and look for it more often (Arricau Bouvery and
Past investigation confirmed that some infections occur frequently in farmers,
where the contact with cattle and sheep is associated with Q fever (Coleman,
2000). Salinas-Melendez et al. (2002) showed
that exposure to C. burnetii is common in animals in the state of Nuevo
Leon Mx. The risk of Q fever on people who work with domestic animals is related
to contact with farm environment rather that any specific animal exposure (Thomas
et al., 1995).
Infection of livestock with C. burnetii often goes unnoticed. Indeed,
sporadic abortion of up to 5% is considered normal and does not prompt investigation.
Furthermore, the lack of overt clinical signs exhibited among infected livestock
make diagnosis a challenge (Cutler et al., 2007).
The zoonosis must be considered as a truly global problem, both in terms of
their distribution and the measures required for their control.
|| Serological status of cattle and sheep against C. burnetii
Q fever is a zoonosis that may occur worldwide, in all geographic and climatic
zones. Coxiella burnetii is a highly infectious agent that is widespread
among livestock around the world (Arricau Bouvery and Rodolakis,
2005). Its resistance to chemical and physical agents is exceptional and
enables the organism to maintain itself in nature without an arthropod vector
and makes air-borne dissemination of infection possible (Little,
The distribution of Boophilus ticks and a high seroprevalence in animals
suggest that these ticks play a role in the transmission and maintenance of
C. burnetii infection in cattle (Schutt et al.,
1976). The feces of ticks infected are heavily contaminated with the microorganisms,
which remain viable for long period of time and therefore may be a potential
source of infection for man and animals (Peacock et al.,
1983). Such infected feces may become powdered and windborne, thereby infecting
the upper respiratory tract of man and animals (Salmon et
al., 1982). Coxiella burnetii was detected in 5 of 10 dust samples
from a barn housing dairy cattle by the PCR (Yanase, 1998).
Because of the polymorphism of the clinical picture and because the diagnosis
is based exclusively on serology, the prevalence of C. burnetii infection
among animals is largely unknown (Rey et al., 2000).
The studies were mostly depend on serological investigation, worldwide and in
Turkey as well (Kalender, 2001).
The ELISA test is more sensitive than the CF test and allows for testing a
greater number of animals and flocks (Rodolakis, 2006).
ELISA and microimmunoflourescence (MIF) tests give similar results with cow
sera, but the ELISA test is more sensitive than the MIF test with goat and sheep
sera (Arricau-Bouvery et al., 2003).
Similar study was performed in Turkey and in Elazıg region. Cetinkaya
et al. (2000) examined 416 cattle and 411 sheep sera by indirect
fluorescent antibody test (IFAT) to determine the prevalence of Q
fever. Seropositivity was observed 5.8% in cattle and 10.5% in sheep. In an
another study (Ozdemir et al., 1999) reported
C. burnetii seropositivity in 33.8% of pregnant and 26.75% of aborted
animals in Elazig and its vicinity using indirect flourescence antibody test.
On the other hand, Kalender (2001) reported seropositivity
in 38.59% of aborted sheep and 11% in sheep given healthy birth.
Furthermore, in a study carried out on 1593 cattle in the Marmara Region, Turkey,
using ELISA, 8.04% was found to be positive to C. burnetii (Yurtalan,
2003). In addition, KiliC et al. (2005) reported
seroprevalence of C. burnetii in 3% of sheep in Aydin and its
In the region of Eastern Anatolia, Seyitoglu et al.
(2006) detected seropositivity in 22.6% of cattle with a history of abortion
and 5.6% in cattle given healthy birth, using ELISA test.
In Europe, there are several studies reporting the seroprevalence of Q fever
using different diagnostic methods. In Italy, Capuano et
al. (2001) detected seropositivity in 14.4% of cattle using IFAT. Masala
et al. (2004) found that 38% of sheep and 47% of goats was seropositive
using ELISA. Parisi et al. (2006) identified
C. burnetii in 11.6% of cattle and 21.5% of sheep and goats using PCR.
Cabassi (2006) detected seroprevalence of 44.9% in aborted
cattle and 22% in healthy cattle using ELISA. In France, Rousset
et al. (2007) found 88% seropositivity in aborted group and 60% in
healthy group using ELISA in 8 goat flocks. Berri et
al. (2007) also examined a goat flock and found that 30% seropositivity
in aborted animals and 80% 6 weeks later after abortion in the same flock by
ELISA. Tellez et al. (1989) used indirect immunofluorescence
test, reported the seroprevalence of Q fever as 76.6% in goat and 17.7% in cattle
in Madrid, Spain. Christoffersen (2007) investigated
seroprevalence of Q fever in Denmark between 2004 and 2006 in cattle using ELISA
and found seropositivity as 35 and 25%, respectively.
Furthermore, Wagner et al. (2005) tested a
total of 744 blood samples (70 Styrian sheep and 674 goats) by CFT for antibodies
to C. Burnetii in Vienna, Austria and found 1.5% seropositivity. Also,
Lausevic (2001) investigated seroprevalence of Q fever
in sheep in Yugoslavia using microagglutination and microimmuneflourescence
and found 5.03% seropositivity.
In USA, studies with concern to Q fever are summarized by McQuiston
and Childs (2002) and reported as 41.6% in goat, 16.5% in sheep and 3.4%
in cattle. In addition, Deforgeand Cone (2006) in California,
seroprevalence of Q fever in 268 bighorn sheep reported to be 10% using complement
In Canada, Hatchette et al. (2002) examined
Q fever seroprevalence between 1997 and 2000 and found an important increase
in seropositivity from 3.1 to 23.5% using microimmuneflourescence test (MIF).
In Mexico, seroprevalence of Q fever in dairy cattle found to be 28%, beef
cattle 10%, goat 35% and 40% in sheep (Salinas-Melendez
et al., 2002).
In Africa, Reinthaler et al. (1988) found that
62.5% of sheep, 53% of goat and 40.4% of cattle using MAT in Southern Sudan,
were seropositive. In Zimbabwe, Kelly et al. (1993)
detected seropositivity to C. burnetii in 39% of cattle, 10% of goats
using IFAT. Furthermore, in Chad, Schelling et al.
(2003) found that 80% of camel, 13% goats, 11% sheep and 4% cattle using
ELISA method, were seropositive. Nakoune et al. (2004)
found 14.3% in cattle using IFAT in Central African Republic. In addition, Cekani
et al. (2008) investigated Q fever seroprevalence in 1656 serum sample
and found 9.8% in sheep and goat and 7.9% in cattle in Algeria using ELISA technique.
In other countries, seroprevalence of Q fever were; 46.6% in cattle, 28.1%
in sheep and 23.5% in goats were observed in Japan using IFAT (Htwe
et al., 1992). In Cyprus, Psaroulaki et
al. (2006) found 48.2% in goats, 24% in cattle, 18.9% in sheep using
IFAT. On the other hand, Loukaides et al.
(2006) found 13.8% using same IFAT in Cyprus.
It is shown that seroprevalence of Q fever is very much changeable with regard to country and even provinces. These alterations is also changeable with regard to test and kit used. Studies regarding to Q fever seroprevalence in Turkey indicated that it varied between 5.6-22.6% in cattle and 3-38.59% in sheep.
The present study indicated that animal population in this region is determined
to be infected with Q fever at 10.9%. Infection rate in cattle was higher (16.3%)
In the seroprevalance studies with concern to cattle and sheep, some found seroprevalance
higher in cattle (Htwe et al., 1992; Psaroulaki
et al., 2006) some in sheep (Schelling
et al., 2003; Cekani et al., 2008).
In the present study, several reasons could play role for the high seroprevalence
observed in cattle. One of the reason is the tick density in the farm which
could be more compared to field and cattle are mainly kept in indoor conditions
in comparison to sheep therefore, seroprevalence were higher in cattle. The
disease morbidity is very high and pathognomonic symptoms of the disease do
not occur. Therefore, challenge against this disease is quite difficult. Thus,
required precautions with regard to animal discharges and vector ticks to be
taken into consideration and effective treatment should be implied.
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