Since its first description in the late 1930s, Q fever has raised many questions. Coxiella burnetii, the causative agent, is a zoonotic pathogen affecting a wide range of hosts. This airborne organism leads to an obligate, intracellular lifecycle, during which it multiplies in the mononuclear cells of the immune system and in the trophoblasts of the placenta in pregnant females. Although some issues about C. burnetii and its pathogenesis in animals remain unclear, over the years, some experimental studies on Q fever have been conducted in goats given their excretion pattern. Goats play an important role in the epidemiology and economics of C. burnetii infections, also being the focus of several epidemiological studies. Additionally, variants of the agent implicated in human long-term disease have been found circulating in goats. The purpose of this review is to summarize the latest research on C. burnetii infection and the role played by goats in the transmission of the infection to humans.

Dogs and cats are potential sources of infection for some zoonotic diseases such as Q fever, caused by Coxiella burnetii, a multiple host pathogen. Q fever outbreaks in dogs and cats have been related with parturition and abortion events, and ticks have a potential role in the transmission of this pathogen. This study aimed to screen for C. burnetii in dogs and cats, and in ticks collected from infested animals. An observational descriptive study was conducted in Portugal at two time points nine years apart, 2012 and 2021. Sera obtained from dogs and cats (total n = 294) were tested for C. burnetii antibodies using a commercial ELISA adapted for multi-species detection. C. burnetii DNA was screened by qPCR assay targeting IS1111 in uterine samples and in ticks. A decrease in the exposure to C. burnetii was observed in cats from 17.2% (95% CI: 5.8–35.8%) in 2012 to 0.0% in 2021, and in dogs from 12.6% (95% CI: 7.7–19.0%) in 2012 to 1.7% (95% CI: 0.3–9.1%) in 2021 (p < 0.05). Overall, and despite differences in the samples, rural habitat seems to favour the exposure to C. burnetii. The DNA of C. burnetii was not detected in ticks. The low seropositivity observed in 2021 and the absence of C. burnetii DNA in the tested samples, suggest that dogs and cats from Portugal are not often exposed to the pathogen. Nevertheless, the monitoring of C. burnetii infection in companion animals is an important tool to prevent human outbreaks, considering the zoonotic potential for owners and veterinarians contacting infected animals, mainly dogs and cats from rural areas which often come into contact with livestock.

Feline infectious peritonitis (FIP) is a severe viral disease with a very high fatality rate. GS-441524 is an adenosine analogue that acts as an antiviral and has shown promise in FIP treatment. However, its commercialization in some regions is not yet authorized. To evaluate the efficacy of GS-441524 based on the published literature, a systematic review was conducted. This systematic review was conducted using PubMed, ScienceDirect, and Google Scholar for studies published from 2018 onwards. Following PRISMA guidelines, 11 studies (totaling 650 FIP cases treated with GS-441524 alone or in combination) were included. Therapeutic efficacy was assessed by FIP form, clinical signs, and dosage. The overall treatment success rate was 84.6%. This rate was higher when GS-441524 was combined with other antivirals and lower in cases of wet FIP or those with neurological complications. Combination therapy with other antivirals may improve outcomes in complicated FIP cases, although further studies are needed. The GS-441524 dosages associated with the best outcomes were 5–10 mg/kg once daily (or equivalent subcutaneous dose), adjusted for FIP type, severity, and presence of neurological/ocular signs. Higher dosages can be used for severe cases or to prevent relapse, but splitting into twice-daily dosing may be necessary to avoid absorption issues. In summary, this synthesis indicates that GS-441524 is a highly promising treatment for FIP, with a high success rate among treated cases. Nevertheless, randomized controlled trials are needed to establish evidence-based therapeutic protocols tailored to different FIP presentations.