**3.2 Reservoirs**

382 A Bird's-Eye View of Veterinary Medicine

spermatozoa cells from patients with Q fever has revealed the presence of attached bacteria.

The incidence of Q fever in human occur very often during spring and early summer when it is warm, dry and windy because the environmental survival allows it to be transported by wind far away from its original source. Such environmental conditions in Jenna (German) in June 2005 caused that *Coxiella burnetii* - infected sheep, grazing and lambing on the meadow

The source of human infections is often unknown, although sheep and goats are more frequently related to Q fever outbreaks in humans (Glisdorf et al., 2005). The largest Q fever outbreaks occurred in the Netherlands, involving 3,921 human cases in the years 2005-2009. The dairy goats and sheep were considered the source of the human Q fever outbreak. The

The infection by ingestion (mainly drinking raw milk) is probably a minor factor of risk, and at present it constitutes even a point of controversy (Maurin & Raoult, 1999; Krumbiegel & Wiśniewski, 1996). Drinking contaminated milk has induced seroconversion in human volunteers but without clinical signs (Benson, 1963). However, some studies have reported clinical diseases linked to the ingestion of cheese (Hatchette et al, 2001; Fishbein & Raoult, 1992) but infection by inhaling contaminated dust or aerosols cannot be excluded. The serological and molecular studies performed in the herds, where antibodies were present in blood of lactating cows, showed that *Coxiella burnetii* DNA was detected in the milk (8.7%). The antibodies were detected only in the serum of 1 % of young cattle selected from these

*Coxiella burnetii* in humans causes highly variable clinical manifestations ranging from acute to fatal chronic infections. Initially, there is typically a noticeable slight increase in internal body temperature lasting for several days. In addition, eye inflammation is stated, as manifested by greater amounts of fluid seromucinous flowing from the conjunctiva sac and nose. These general symptoms do not give rise to suspicion of Q fever. Sometimes only the prevalence of many cases of people with the acute symptoms of flu can indicate the occurrence of the disease in animals. It comes more often to premature births and miscarriages. Swelling and local haemorrhages can be observed in the placenta of infected animals. The further course of disease depends on the degree of virulence of the agent and the immune status of animals. Acute form of Q fever is mainly a flu-like disease, atypical pneumonia or hepatitis. Atypical pneumonia is characterised by fever, headache and myalgia. Despite the prevalence of pneumonia, cough can be absent. The hepatitis could be asymptomatic, only with the raise of transaminase levels, or the infectious hepatitis - rarely

In about 5% of the cases, the disease may become chronic form and it can lead to the endocarditis, chronic fatigue syndrome or repeated abortions. Endocarditic is the most frequent. It represents 1.5 - 2.5% all human cases of endocarditis. Chronic fatigue syndrome is characterised by an inappropriate fatigue, myalgia, arthralagia, night sweats and changes in mood. This chronic forms occur very often in Australia (Arricau-Bouvery & Rodolaski, 2005). In pregnant women, *Coxiella burnetii* can cause placentitis leading to abortion, neonatal death, premature birth and low birth weight. The risk of chronic Q fever leading to repeating miscarriages, is very high when the infection occurs during pregnancy (Arricau-

bordering a residential brought about infection in 331 human (Gildsdorf et al., 2007).

disease was found in about 60 farms these animals (Roest et al., 2011).

(Kruszewska et al., 1993, 1996).

herds (Muskens, 2011).

with jaundice (Fournier et. al., 1998).

Cattle, goats and sheep are considered the primary reservoirs that human contamination comes from. Epidemiological data indicated that dairy cows are more frequently chronically infected than sheep, and they are the most important source of human infections. The duration time of *Coxiella burnetii* excretion in infected animals depends on species and type of samples tested (Arricau-Bouvery N. & Rodolakis, 2005) (Tab. 1).

Ticks have been considered a reservoir and a vector of *Coxiella burnetii*. In the nature, there are about 40 species of ticks transmitting the infections including *Rihicephalus sanguineus*, *Amblyomma triuguattum* (Maurin & Raoult, 1999). The infection is transmitted from one stage to the next in the ticket cycle, and transovarian infection is observed. Ticks become infected after ingestion of infected mammal blood that in the time of the bacteremia. Microorganisms multiply mainly in the epithelial cells of the middle tick gut, then penetrate the intestinal wall, hemocytes and connective tissue of internal organs. Hence an infected tick is a carrier of the *Coxiella burnetii* for life, and its saliva may contain very high concentration of agent (108 – 1011) (Niemczuk, 2010). *Coxiella burnetii* in ticks, as in mammals, are in phase I and they are highly infectious. Morover, ticks are not considered essential in the natural cycle of *Coxiella burnetii* infections in livestock because animals can have many other opportunities to become infected. Ticks may play a significant role in the transmission of coxiellosi among the wild birds and vertebrates such as rodents and lagomorphs (Maurin & Raoult, 1999).

Cats and dogs may be reservoirs of *C. burnetii*. Dogs may be infected by tick bite, consumption of placentas or milk from infected ruminants, and the aerosol route. In the literature, the cases of Q fever human infections after contact with parturient cats are described in Nova Scotia (Kosatsky, 1984). Moreover, wild mammals, including horses, rabbits, swine, camels, water buffalo, rats and mice constitute the reservoirs of *Coxiella burnetii*. The serological studies of rats in the UK have shown anti-phase II antibody seroprevalences ranging from 7 to 53% among wild brown rat populations (Webster et al., 1995).

Birds, including pigeons, chickens, ducks, geese and turkeys can be infected with coxiellosis. Infected domestic poultry can be the sources of infections in human. People become infected by consumptions of raw eggs or inhalation of infected fomites (Maurin & Raoult, 1999).

According to world experts on counter-terrorism, the agent that causes Q fever, is considered as an effective component of biological weapon (Arricau & Rodolaski, 2005). It is a potential agent of bioterrorism because of its accessibility, low infection dose, resistance to environmental degradation, and aerosol route of transmission. The minimum number of pathogens is required for human infection is 1-10 microorganisms. According to WHO, 50 kilograms of powder containing *Coxiella burnetii* can cause the comparable number of cases to tularemia or anthrax (Spicer, 1994; Moquin 2002). Q fever, although not characterised by high mortality, is important in wartime because the disease is severe, and the patient requires long-term care. Furthermore, the high resistance of the bacteria to drying, moisture, high or low temperature, promotes long-term being in the air, on skin, wool and straw

Epidemiology, Zoonotic Aspect and Current Epidemiological Situation of Q Fever in Poland 385

soluble vaccine containing trichloroacetic acid-extracted antigen from phase I *Coxiella burnetii* nine mile strain was successfully used in Czechoslovakia. In animal, the vaccines composed of inactivated whole phase I bacteria are the most effective. Bacterial shedding in milk and placentas was strongly reduced in infected animals vaccinated with phase I vaccines. Available vaccines are prepared with a single strain and therefore, they are monovalent. The recent works have shown that the vaccines reduce the shedding of *Coxiella burnetii.* These results are very important because of limiting the clinical disease in animals

The diagnosis of Q fever remains difficult and epidemiological studies. Regarding the diagnosis of Q fever, several tools are available for direct and indirect detection of C*oxiella burnetii*. The studies are often based on the serological investigations. Although, the serological methods are useful. They do not allow for the identification of *Coxiella burnetii* shedding animals. Some infected animals can be seropositive without sheding *Coxiella burnetii*, and the others can shed the bacteria and remain seronegative, what is of great concern and could have an important impact both on animal and public health. Moreover, the serological test can distinguish vaccinated and naturally infected animals. The complement fixation test (CFT) was proposed as an alternative test for international trade by the Office International des Epizooties (OIE). Additionally, alternative tests such as enzymelinked immunosorbent assay (ELISA) and indirect immunofluorescence assay (IFA) can be used for diagnosis Q fever within a local context, and it can also be used during importing and exporting animals following bilateral agreements. At present, there are three ELISA commercial kits for diagnosis Q fever in domestic ruminants whereas commercial kits using the IFA for veterinary investigation are not available. The diagnosis of Q fever is based on the serological test and the immunofluorescence assay. The ELISA and IFA tests are more sensitive than the CFT for detection of antibody response in animals or humans with acute Q fever but not for the detection of antibody response in humans with chronic Q fever and in aborting cows (Sidi-Boumedine et al., 2010). The ELISA and IFA detect antibody in acutephase sera, and they are quite efficient in binding IgM (these antibodies predominante in the acute stage), in contrast to the CF test. Recent infections are difficult to demonstrate serologically by the CFT, because antibodies detected by this test can persist longer than acute stage. However, chronic and persistent infections of *Coxiella burnetii* are difficult to diagnose by the ELISA, because this test is more accurate in the acute stage of Q fever, when the IgM predominate in the response (Jóźwik et al., 2007). Cross-reactions are the biggest source of false negative results during interpreting serological results. Cross-reactions have been described between *Coxiella burnetii* and *Legionella pneumophila* (Deyer et al., 1988; Finidori et al., 1992)*, Legionella micdadei* (Musso & Raoult, 1997), and *Bartonella quintana* and

Other techniques used for Q fever diagnosis include dot immunobloting, Western blotting, indirect hemolysis test and radioimmunoassay. Western blotting has been reported to be sensitive and specific. The molecular masses of antigens detected vary from 10 to 100 kDa. Antibodies reacting with 50, 80, 160 kDa antigens are considered indicative of chronic Q fever (Blondeau et al, 1990). However Western blotting is very time consuming technique and the results obtained by this technique are not reproducible. Dot blotting and radioimmunobloting

and human (Arricau-Bouvery & Rodolaski, 2005).

*Bartonella henselae* (La Scola & Raoult, 1996).

**5. Laboratory diagnosis** 

(Prusakowski, 2001), for example experiencing up to 2 years in human faeces, to 6 years in the ticks' feces, 2-3 years in the water, 1 year in the fur, 1 month in meat, and 1-2 months in dairy products (Little, 1999; Maurin & Raoult, 1999). Physical factors and especially pasteurisation kills germs in 15 seconds, while ultraviolet radiation is not an effective way to get rid of this microbe.
