High prevalence and risk factors of Coxiella burnetii in milk of dairy animals with a history of abortion in Iran

Molecular investigation of Coxiella burnetii in aborted fetus of small ruminants in southeast Iran

The domestic animal, known as a main reservoir of Coxiella burnetii, is susceptible to the occurrence of coxiellosis, which can lead to abortions in domestic animals, causing significant economic damage and posing risks to human health. Therefore, the purpose of this study is to investigate C. burnetii as the causative agent of Q fever in abortion samples of small ruminants in southeastern Iran. This study was conducted between 2020 and 2021 in Zarand city, located in Kerman province (southeast Iran). In this study, 50 abomasum swab samples of aborted sheep and goat fetuses were collected and analyzed using molecular methods to identify C. burnetii. The results revealed that 26% (n: 13) of the collected abortion samples were infected with C. burnetii. Among the positive samples, two (50%) belonged to goat abortion samples while 11 (23.9%) belonged to sheep abortion samples. This study demonstrates that C. burnetii is one of the causes of abortion in small ruminants in southeastern Iran. It is recommended to pay more attention to C. burnetii in domestic animals due to its significant economic impact on livestock and its potential implication for human health in Iran.

Molecular examination for Coxiella burnetii and Brucella spp. infections in Iranian women experiencing spontaneous miscarriage

BACKGROUND

Spontaneous miscarriage, a leading health concern globally, often occurs due to various factors, including infections. Among these, Coxiella burnetii and Brucella spp. may have adverse effects on pregnancy outcomes. While previous research has established a link between infections and spontaneous miscarriage, our study aimed specifically to investigate the presence of these two pathogens in abortion samples from women who experienced spontaneous miscarriages in Iran. Our study can add to the existing knowledge by focusing on Iran, a region with a high prevalence of C. burnetii and Brucella spp. As a result, it could provide a better understanding and unique insights into the relationship of these pathogens with spontaneous miscarriages in endemic regions.

METHODS

From March 2021 to March 2022, a total of 728 abortion samples (including placenta and cotyledon) were collected from 409 women who had experienced spontaneous miscarriages in the provinces of Tehran, Fars, and West Azerbaijan in Iran. The specimens included 467 Formalin-Fixed Paraffin-Embedded (FFPE) and 261 fresh frozen samples. After DNA extraction from abortion samples, the quantitative real-time PCR (qPCR) assay targeted a specific fragment of the IS1111 and IS711 elements for molecular identification of C. burnetii and Brucella spp., respectively. Furthermore, the qPCR assay employing specific primers for different species was used to determine the species of Brucella.

RESULTS

Among the studied women, 1 out of 409 (0.24%) samples tested positive for Brucella spp., specifically Brucella melitensis. There were no positive specimens for C. burnetii.

CONCLUSIONS

Our study contributes to understanding the potential involvement of Brucella species in spontaneous infectious abortion within endemic regions. The identification of B. melitensis in this study highlights the need for further research in this area. However, while our results suggest a relatively low or zero identification of these pathogens in our sample population, this does not rule out the possibility of undetected infections. Therefore, it is critical to acknowledge the limitations of the molecular techniques used (qPCR), which may have potential limitations such as sensitivity and specificity. Moreover, because 64.15% of our samples were FFPE, the sensitivity of the qPCR test may be reduced. These raise concerns about the accuracy of the reported prevalence rates and the potential for false positives or negatives.

Genotyping and phylogenetic analysis of Coxiella burnetii in domestic ruminant and clinical samples in Iran: insights into Q fever epidemiology

Coxiella burnetii, a zoonotic pathogen, is the causative agent of Q fever, an endemic disease in Iran. However, there is currently a lack of available data on the genotypes of C. burnetii in the country. Here, we typed 26 C. burnetii isolates detected in milk, abortion, cotylodon, and cardiac valve samples from various geographical areas and hosts (7 cattle, 8 goats, 10 sheep, and 1 human) using Multilocus Variable Number Tandem Repeat Analysis (MLVA/VNTR) with five loci:ms24, ms27, ms28, ms33, and ms34. As IS1111 was observed to be spontaneously inserted in locus ms23 across all of our examined C. burnetii samples, five loci were employed for MLVA/VNTR genotyping. Among the 26 C. burnetii strains, 22 distinct genotypes (A-V) were identified in the discriminative loci. In silico analysis categorized Iranian C. burnetii strains into five genomic groups along with seven singletons, representing 11 exiting clonal complexes worldwide. Clusters 10 and 11 exclusively consisted of Iranian samples. These findings revealed high genotyping diversity among C. burnetii isolates in Iran. The genotypes circulating in Iran differed significantly from those found in other regions worldwide. To gain a comprehensive understanding of Q fever epidemiology in Iran, it is crucial to conduct large-scale studies that assess the distribution of C. burnetii genotypes across different geographical areas, hosts, and sources.

The epidemiological survey of Coxiella burnetii in small ruminants and their ticks in western Iran

Background

Q fever is one of the most important zoonotic diseases caused by Coxiella burnetii. Although Q fever is an endemic disease in Iran, epidemiological data on C. burnetii infection are not yet complete in reservoirs and vectors in some parts of Iran. This survey investigated C. burnetii infection in small ruminants (sheep and goat blood samples) and their ticks in western Iran (Kurdistan province) in 2020. The presence of C. burnetii DNA was identified in these samples by targeting the IS1111 gene using the quantitative PCR (qPCR) method.

Results

Out of 250 blood samples (232 sheep and 18 goats), C. burnetii was detected in two samples (0.8%) belonging to the sheep (0.9%). In addition, 34 of 244 collected ticks (13.9%) from infested animals (244) were positive for C. burnetii infection. The highest prevalence of infection was found in Dermacentor marginatus (18.3%) and Haemaphysalis concinna (12.5%).

Conclusions

The present study showed that ticks could have a possible role in the epidemiology of Q fever in Iran.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-022-03396-0.

Identification of Immunogenic Linear B-Cell Epitopes in C. burnetii Outer Membrane Proteins Using Immunoinformatics Approaches Reveals Potential Targets of Persistent Infections

Coxiella burnetii is a global, highly infectious intracellular bacterium, able to infect a wide range of hosts and to persist for months in the environment. It is the etiological agent of Q fever—a zoonosis of global priority. Currently, there are no national surveillance data on C. burnetii’s seroprevalence for any South American country, reinforcing the necessity of developing novel and inexpensive serological tools to monitor the prevalence of infections among humans and animals—especially cattle, goats, and sheep. In this study, we used immunoinformatics and computational biology tools to predict specific linear B-cell epitopes in three C. burnetii outer membrane proteins: OMP-H (CBU_0612), Com-1 (CBU_1910), and OMP-P1 (CBU_0311). Furthermore, predicted epitopes were tested by ELISA, as synthetic peptides, against samples of patients reactive to C. burnetii in indirect immunofluorescence assay, in order to evaluate their natural immunogenicity. In this way, two linear B-cell epitopes were identified in each studied protein (OMP-H_(51–59), OMP-H_(91–106), Com-1_(57–76), Com-1_(191–206), OMP-P1_(197–209), and OMP-P1_(215–227)); all of them were confirmed as naturally immunogenic by the presence of specific antibodies in 77% of studied patients against at least one of the identified epitopes. Remarkably, a higher frequency of endocarditis cases was observed among patients who presented an intense humoral response to OMP-H and Com-1 epitopes. These data confirm that immunoinformatics applied to the identification of specific B-cell epitopes can be an effective strategy to improve and accelerate the development of surveillance tools against neglected diseases.

Molecular detection of Coxiella burnetii infection in aborted samples of domestic ruminants in Iran

BACKGROUND

Coxiella burnetii is the causative agent of Q fever which is a highly infectious zoonotic disease. C. burnetii has become one of the most important causes of abortion in livestock, which can lead to widespread abortions in these animals. There are very limited studies on the prevalence of C. burnetii infection in cases of animal abortion in Iran. The aim of this study was to investigate the occurrence of C. burnetii in ruminant abortion samples in Iran.

METHODS

Abortion samples from cattle, sheep and goats were collected from different parts of Iran and were tested using Real-time PCR targeting the IS1111 element of C. burnetii.

RESULTS

In this study, 36 samples (24.7%) of the 146 collected samples were positive for C. burnetii. The prevalence of C. burnetii was 21.3% (20 of 94 samples) in sheep samples. Also, 10 of 46 cattle samples (21.7%) were positive. All six goat abortion samples were positive for C. burnetii.

CONCLUSIONS

The findings of the study demonstrate that C. burnetii plays an important role in domestic ruminant abortions in Iran, suggesting that more attention should be paid to the role of C. burnetii in domestic animal abortions by veterinary organizations. The risk of transmitting the infection to humans due to abortion of animals should also be considered.

Identification of Coxiella burnetii in Raw Milk of Livestock Animal in Iran

Coxiella burnetii is the causative agent of Q fever in humans and animals. This study aimed to determine the frequency of C. burnetii in milk samples of dairy animals (goats, sheep, and cattle) in some selected regions in Iran, where there is no information about prevalence of C. burnetii. In this study, 162 individual milk samples were collected from 43 farms in three provinces (Tehran, Hamadan, and Mazandaran). Real-time PCR was used for the detection of IS1111a element of C. burnetii. In total, 23 of 162 samples (14.2%, 95% confidence interval (CI): 9.65–20.2%) were positive for C. burnetii by real-time PCR. C. burnetii was detected in 10.17% (95% CI: 4.74–20.46) of goat milk samples. In sheep milk samples, 18.6% (95% CI: 9.74–32.62) were positive, and C. burnetii was detected in 15% (95% CI: 8.1–26.11) of cattle milk samples. Molecular evidence of the presence of C. burnetii was seen in milk samples of dairy animals in all the studied regions. These findings demonstrated that C. burnetii infection, especially in raw milk samples, deserves more attention from the health care system and veterinary organization in Iran.

Molecular prevalence of Coxiella burnetii in bulk-tank milk from bovine dairy herds: Systematic review and meta-analysis

Coxiella burnetii is an obligate intracellular zoonotic bacterium that causes Q fever. Ruminants, including cattle, are broadly known to be reservoirs for this bacterium. Since 2006, many research groups have evaluated the herd-level prevalence of C. burnetii in cattle by molecular techniques on composite milk samples. This study explored the global C. burnetii herd-level prevalence from studies done on bovine bulk-tank milk (BTM) samples using PCR-based analysis. Also, moderators were investigated to identify sources of heterogeneity. Databases (CAB Abstracts, Medline via Ovid, PubMed, Web of Science and Google Scholar) were searched for index articles on C. burnetii prevalence in BTM samples by PCR published between January-1973 and November-2018. Numerous studies (1054) were initially identified, from which seventeen original publications were included in the meta-analysis based on the pre-defined selection criteria. These studies comprised 4031 BTM samples from twelve countries. A random-effects model was used because of considerable heterogeneity (I² = 98%) to estimate the herd-level prevalence of C. burnetii as 37.0%(CI_95%25.2–49.5%). The average herd size appeared to account for a high level of the heterogeneity. No other moderators (geographic location, gross national income or notification criteria for Q fever) seemed to be determinant. This systematic evaluation demonstrated a high molecular prevalence of C. burnetii in BTM samples both in European and non-European countries, evidencing a widespread herd-level circulation of this agent in bovine dairy farms around the world. Meta-regression showed herd size as the most relevant moderator with the odds of a BTM sample testing positive doubling with every unit increase.

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First meta-analysis of the PCR-based prevalence of C. burnetii in bovine milk

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Results showed a high molecular prevalence of C. burnetii in bulk-tank milk samples.

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C. burnetii is widely distributed in dairy farms in Europe and the wider world.

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Current results reinforce the need for further investigations on this zoonosis.

Molecular detection of Coxiella burnetii in livestock farmers and cattle from Magdalena Medio in Antioquia, Colombia

Coxiella burnetii causes Q fever in humans and coxiellosis in animals. In humans, it causes acute febrile illnesses like influenza, pneumonia, hepatitis, and chronic illnesses such as endocarditis, vascular infection, and post-infectious fatigue syndrome. It is widely distributed worldwide, and its main reservoirs are sheep, goats, and cattle. This study aimed to determine the frequency of C. burnetii infection using molecular detection and to identify the associated factors in livestock farmers and cattle from the Magdalena Medio region of Antioquia, Colombia. Using real-time polymerase chain reaction (PCR), molecular detection was performed for the IS1111 insertion sequence of C. burnetii using genomic DNA collected from the peripheral blood of 143 livestock farmers and 192 cattle from 24 farms located in Puerto Berrío, Puerto Nare, and Puerto Triunfo. To confirm the results, bidirectional amplicon sequencing of 16S rRNA was performed in four of the positive samples. Additionally, factors associated with C. burnetii were identified using a Poisson regression with cluster effect adjustment. Real-time PCR showed positive results in 25.9% and 19.5% of livestock farmer samples and cattle samples, respectively. For livestock farmers, factors associated with C. burnetii were the area where the farm was located [Puerto Berrío, adjusted prevalence ratio (aPR): 2.13, 95% confidence interval (CI): 1.10-4.11], presence of hens (aPR: 1.47, 95% CI: 1.21-1.79), horses (aPR: 1.61, 95% CI: 1.54-1.67), and ticks (aPR: 2.36, 95% CI: 1.03-5.42) in the residence, and consumption of raw milk (aPR: 1.47, 95% CI: 1.26-1.72). For cattle, the factors associated with Coxiella genus were municipality (Puerto Nare; aPR: 0.39, 95% CI: 0.37-0.41) and time of residence on the farm (≥49 months; aPR: 2.28, 95% CI: 1.03-5.20). By analyzing sequences of the 16S rRNA molecular marker, C. burnetii infection was confirmed in livestock farmers. However, in cattle, only the presence of Coxiella-type bacteria was identified. Further research is necessary to determine the potential role that these types of bacteria have as etiological agents for disease in livestock farmers and cattle from the study area.

Prevalence of Coxiella burnetii in milk collected from buffalo (water buffalo) and cattle dairy farms in Northwest of Iran

The present study was conducted to determine the prevalence of C. burnetii in raw milk samples collected from water buffalos and cattle in Northwest of Iran (West Azerbaijan Province). A total number of 840 milk samples were randomly collected from buffalos and cattle belonged to three different geographical regions in west Azerbaijan (the map is necessary). The milk samples were collected seasonally during 2018 and the age of animals were recorded. All the milk samples were subjected to DNA extraction. Nested-PCR was used to detect C. burnetii based on the transposable gene IS1111. The results showed that 16.9% (95% CI: 14.5%-19.6%) of the examined milk samples (19.3% buffalo and 14.6% cattle samples) were positive for C. burnetii. There was a significant difference in C. burnetii shedding in milk between different age groups in cattle but not in buffalos (p value <0.05). The shedding of C. burnetii in milk was highly prevalent in summer (31.1%) (p < 0.05, 95% CI: 26.1%-38.4%). There were significant regional and seasonal variations in the prevalence of C. burnetii in the examined milk samples. It was concluded that buffalo population in west Azerbaijan should be considered as an important factor in the epidemiology of Q fever and consequently in public health.