Potential Animal and Environmental Sources of Q Fever Infection for Humans in Queensland

Abstract

Q fever is a vaccine-preventable disease; despite this, high annual notification numbers are still recorded in Australia. We have previously shown seroprevalence in Queensland metropolitan regions is approaching that of rural areas. This study investigated the presence of nucleic acid from Coxiella burnetii, the agent responsible for Q fever, in a number of animal and environmental samples collected throughout Queensland, to identify potential sources of human infection. Samples were collected from 129 geographical locations and included urine, faeces and whole blood from 22 different animal species; 45 ticks were removed from two species, canines and possums; 151 soil samples; 72 atmospheric dust samples collected from two locations and 50 dust swabs collected from domestic vacuum cleaners. PCR testing was performed targeting the IS1111 and COM1 genes for the specific detection of C. burnetii DNA. There were 85 detections from 1318 animal samples, giving a detection rate for each sample type ranging from 2.1 to 6.8%. Equine samples produced a detection rate of 11.9%, whilst feline and canine samples showed detection rates of 7.8% and 5.2%, respectively. Native animals had varying detection rates: pooled urines from flying foxes had 7.8%, whilst koalas had 5.1%, and 6.7% of ticks screened were positive. The soil and dust samples showed the presence of C. burnetii DNA ranging from 2.0 to 6.9%, respectively. These data show that specimens from a variety of animal species and the general environment provide a number of potential sources for C. burnetii infections of humans living in Queensland. These previously unrecognized sources may account for the high seroprevalence rates seen in putative low-risk communities, including Q fever patients with no direct animal contact and those subjects living in a low-risk urban environment.

Serological evidence of Coxiella burnetii infection among companion dogs in Fars Province, South Iran

“…However, present research and some other previous reports showed that there was no correlation between seropositive cases and direct contact with farm animals (Gale et al, 2007;Tozer et al, 2014). It was hypothesised that other risk factors (except farm animals contact) like wildlife contact, tick exposure or pet-owners who worked closely with other farm animals would have a positive association with seropositivity to C. burnetii in the pets (Cooper et al, 2011).…”

“…In present study, breed, type of housing, type of food and presence of clinical signs showed no significant differences between positive and negative cases. Based on the literature, high prevalence of C. burnetii has been reported in the urine of dogs and human infection has been directly linked to the pet dogs (Komiya et al, 2003;Tozer et al, 2014). Therefore, no clinical signs of positive cases might have a decisive role in human infections.…”

Host and Environmental Factors Modulate the Exposure of Free-Ranging and Farmed Red Deer (Cervus elaphus) to Coxiella burnetii

“…Although the majority of human Q fever outbreaks are linked to the transmission of C. burnetii from domestic ruminants (4,5), the ability of C. burnetii to infect wild hosts (3,6) and its high environmental resistance (1) make wildlife species potential reservoirs of C. burnetii. Based on this hypothesis, wildlife could maintain C. burnetii and transmit it to wildlife (7), domestic animals (8), or humans (9). It is therefore of paramount relevance (i) to identify those potential wild reservoir species that could, through direct and indirect interactions, transmit C. burnetii to target species (domestic animals and humans) and (ii) to determine which environmental factors are the main drivers of C. burnetii within the most relevant wild reservoirs.…”

Bacterial canine vector-borne zoonotic diseases in “One Health” concept

“…In Canada, a dog-related outbreak of Q fever was reported [135]. Although arthropod-borne transmission of Q fever in humans is not considered to be significant, C. burnetii has been isolated from ticks collected from dogs [136], and as ticks shed high loads of bacteria in their feces and saliva, they may be another potential source of bacterial transmission.…”