Q fever during pregnancy: a narrative review

Molecular detection of Coxiella burnetii in tick and blood samples from small ruminants in northwest of Iran

This survey sought to molecularly detect Coxiella burnetii in Argasidae and Ixodidae ticks attached to small ruminants in the region of West Azerbaijan (Northwest of Iran) and blood samples collected from the same animals. 451 tick samples and 927 blood samples were obtained from sheep (n = 536) and goats (n = 391) and tested by nested PCR for detection of C. burnetii insertion sequence IS1111 or icd gene sequence. The collected ticks were morphologically classified as Rhipicephalus sanguineus, Rhipicephalus turanicus, Hyalomma asiaticum, Hyalomma anatolicum, or Argas reflexus. 14% of ticks (65 in total 43 for IS1111 and 22 for icd gene) tested positive for C. burnetii, none of which were from the Argas genus. Among the 927 blood samples, 218 (23.5%) tested positive for C. burnetii. The positive result from analysis targeting the genes IS1111 and icd were 131 and 87 respectively. As Q fever is a tickborne zoonosis and endemic to Iran, such information is critical for creating effective, coordinated, and strategic tick and pathogen control programs to prevent disease outbreak in domestic animals and humans.

Coxiella burnetii seroprevalence in domestic goat does in the United States: Prevalence, distribution, and associated risk factors

Infection with the bacterium Coxiella burnetii can cause coxiellosis in animals and Q fever in humans. Coxiellosis a consistently underreported infectious disease. The infection can result in reproductive consequences for humans and animals. Ruminants are a reservoir for infection and humans are generally infected via aerosolized secretions, making it a public health concern. Studies of ruminant seroprevalence are generally limited in size and scope. This study determined seroprevalence in a large-scale U.S. population of female goats using serum samples from 7736 does from 24 states. This study identified C. burnetii seroprevalence in the United States domestic goat population. Overall, 14.5 % (SE = 2.3) of does were seropositive and 21.0 % (SE = 2.4) of operations had at least 1 seropositive doe. Further, operation demographics and herd management practices associated with seropositivity were as follows: the suspected or confirmed presence of caprine arthritis encephalitis (CAE), caseous lymphadenitis (CL), Johne's disease, or sore mouth in the herd in the previous 3 years, not cleaning or disinfecting the kidding areas or removing aborting does from other does, allowing visitors to access the kidding areas, and a lower percentage of adult goat inventory that were adult bucks or wethers. Furthermore, goat breed was associated with seropositivity. These data show C. burnetii seroprevalence in the United States and identify operation and animal characteristics and management practices associated with C. burnetii seropositivity. Together, this information can be used to help limit animal transmission, inform public health measures, and help educate and protect individuals working with goats.

Prevalence, Risk Factors, and Relationship between Reproductive Performance and the Presence of Antibodies against Coxiellosis in Dairy Farm Milk Tanks in the Northwest of Spain

Q fever is a zoonotic disease that has been associated with reproductive problems in animals. As there is little epidemiological data regarding the distribution and risk factors of this disorder in cattle, the objective of this study was to evaluate the prevalence of Coxiella burnetii among dairy herds in the northwest of Spain, and to determine the on-farm risk factors associated with the disease and its effects on reproductive performance. Bulk tank milk (BTM) samples were collected from 262 commercial dairy herds from A Coruña, Lugo, and Pontevedra provinces. Data about location, mean age, and herd management features were obtained. A commercial indirect ELISA kit was used to determine the presence of antibodies against C. burnetii in BTM samples. The relationship between seropositivity to C. burnetii and the risk factors was checked using a Pearson's χ2 test and a classification tree analysis. In addition, a one-way ANOVA test and the Mann-Whitney U test were used to check the impact of seropositivity to C. burnetii on reproductive performance. A total of 60.1% of the farms tested positive for coxiellosis, the herd size, the external purchase of livestock, and the geographical area were identified as the main risk factors. Conception rate and first-service conception rate were significantly lower (p < 0.05) in positive farms (37.1 and 32.9%) compared to negative farms (39.8 and 36.1%). Similarly, positive farms had significant higher incidence of endometritis (13.7% vs. 11.2%, p < 0.05). Consequently, a high seropositivity and slightly negative effects of coxiellosis on reproductive performance were observed, which intensifies the need for further research, including the identification an active infection in positive herds and the characterization of the genotype.

Q fever screening among pregnant women with pre-term delivery in northern Israel: An observational study

The relationship between Q fever, caused by Coxiella burnetii, and obstetrical complications is debatable. Since Q fever is endemic in Israel, we aimed to assess its seroprevalence and clinical characteristics in pre-term deliveries. Between 1 August 2017 and 31 December 2019, we conducted serological screening for C. burnetii in pregnant women who presented to Rambam Health Care Campus with pre-term delivery (before 37 weeks of gestation). Anti-C. burnetii antibodies were tested first by enzyme-linked immunosorbent assay for the detection of phase I-IgG, phase II-IgG and phase II-IgM. Positive results were confirmed by indirect immunofluorescence with titre determination. Seropositivity was classified into past, acute and chronic infection. Demographic and clinical data of mothers and neonates were collected and compared between seropositive and seronegative women. Out of 386 pregnant women screened for anti-C. burnetii antibodies, 16 (4.1%) were seropositive, of whom three were diagnosed with past, 12 with acute and one with chronic infection. A higher percentage of seropositive women were immunosuppressed, 2/16 (12.5%) compared with 7/370 (1.9%) in seronegative women, (p = .05). Neonates with small for gestational age were born to 2/16 (12.5%) seropositive women compared with 29/370 (7.8%) to seronegative women, (p = .35). The seroprevalence of Q fever among pregnant women with pre-term birth reached 4% in northern Israel. This high rate in an endemic setting encourages investigating the role of routine screening for Q fever during pregnancy. Special attention should be given to pregnant immunosuppressed women at risk for exposure to Q fever.

Infection and Persistence of Coxiella burnetii Clinical Isolate in the Placental Environment

Infection by Coxiella burnetii, the etiological agent of Q fever, poses the risk of causing severe obstetrical complications in pregnant women. C. burnetii is known for its placental tropism based on animal models of infection. The Nine Mile strain has been mostly used to study C. burnetii pathogenicity but the contribution of human isolates to C. burnetii pathogenicity is poorly understood. In this study, we compared five C. burnetii isolates from human placentas with C. burnetii strains including Nine Mile (NM) as reference. Comparative genomic analysis revealed that the Cb122 isolate was distinct from other placental isolates and the C. burnetii NM strain with a set of unique genes involved in energy generation and a type 1 secretion system. The infection of Balb/C mice with the Cb122 isolate showed higher virulence than that of NM or other placental isolates. We evaluated the pathogenicity of the Cb122 isolate by in vitro and ex vivo experiments. As C. burnetii is known to infect and survive within macrophages, we isolated monocytes and placental macrophages from healthy donors and infected them with the Cb122 isolate and the reference strain. We showed that bacteria from the Cb122 isolate were less internalized by monocyte-derived macrophages (MDM) than NM bacteria but the reference strain and the Cb122 isolate were similarly internalized by placental macrophages. The Cb122 isolate and the reference strain survived similarly in the two macrophage types. While the Cb122 isolate and the NM strain stimulated a poorly inflammatory program in MDM, they elicited an inflammatory program in placenta macrophages. We also reported that the Cb122 isolate and NM strain were internalized by trophoblastic cell lines and primary trophoblasts without specific replicative profiles. Placental explants were then infected with the Cb122 isolate and the NM strain. The bacteria from the Cb122 isolate were enriched in the chorionic villous foetal side. It is likely that the Cb122 isolate exhibited increased virulence in the multicellular environment provided by explants. Taken together, these results showed that the placental isolate of C. burnetii exhibits a specific infectious profile but its pathogenic role is not as high as the host immune response in pregnant women.

Seroprevalence and Risks Factors Associated with Coxiella burnetii Infection in Slaughterhouse Zebu Cattle (Bos indicus) from Northern Regions of Cameroon

A study was conducted to determine the seroprevalence and risks factors of Coxiella burnetii in zebu cattle from the northern regions of Cameroon. From a total of 2016 (1754 females and 262 males) sera sampled, 801, 762 and 453 were collected, respectively, from Adamawa, North and Far North, and screened for Coxiella burnetii using indirect enzyme-linked immunosorbent assay (iELISA). A total of 23.76% (479/2016) were serologically positive. The seroprevalence of Adamawa, North and Far North were 29.09% (233/801), 19.95% (152/762) and 20.75% (94/453); respectively. The seropositivity of male and female were 4.58% and 26.62%; respectively. Cattle from Adamawa region were more likely to have been exposed to C. burnetii than animals from Far North region (OR = 3.28; 95%CI: 1.13-7.85; p = 0.02). The Gudali breed was significantly more infected than Aku (OR =2.52; 95%CI: 1.06-5.99; p = 0.03), and animals aged of (6-9) years were 1.89 times more likely to have been infected to C. burnetii than young animals (p = 0.03). The seropositivity to this bacterium was significantly associated to pregnant cattle than non-pregnant (OR = 1.71; 95%CI: 1.01-2.90; p = 0.04). Female cattle were more likely to have been infected by C. burnetii than male and the rainy season were 1.66 more associated to this disease than dry season. The linear regression model indicated that C. burnetii seropositivity were positively correlated to the regions (0.09, CI: 0.04; 0.18; p = 0.007), age (0.01, CI: -0.01; 0.04; p = 0.02), sex (0.19, CI: 0.08-0.32, p = 0.001) and physiological status (0.11, CI: -0.04; 0.26; p = 0.006). This study revealed that C. burnetii infection is widespread among zebu cattle of Adamawa, North and Far North of Cameroon.

From Coxiella burnetii Infection to Pregnancy Complications: Key Role of the Immune Response of Placental Cells

The infection of pregnant animals and women by Coxiella burnetii, an intracellular bacterium, compromises both maternal health and foetal development. The placenta is targeted by C. burnetii, as demonstrated by bacteriological and histological evidence. It now appears that placental strains of C.&nbsp;burnetii are highly virulent compared to reference strains and that placental injury involves different types of placental cells. Trophoblasts, the major placental cells, are largely infected by C. burnetii and may represent a replicating niche for the bacteria. The placenta also contains numerous immune cells, including macrophages, dendritic cells, and mast cells. Placental macrophages are infected and activated by C. burnetii in an unusual way of M1 polarisation associated with bacterial elimination. Placental mast cells eliminate bacteria through a mechanism including the release of extracellular actin filaments and antimicrobial peptides. In contrast, C. burnetii impairs the maturation of decidual dendritic cells, favouring bacterial pathogenicity. Our aim is to review C. burnetii infections of human placentas, paying special attention to both the action and function of the different cell types, immune cells, and trophoblasts targeted by C. burnetii in relation to foetal injury.