Epidemiology of Q fever in Iran: A systematic review and meta-analysis for estimating serological and molecular prevalence

Global and regional seroprevalence of coxiellosis in small ruminants: A systematic review and meta-analysis

BACKGROUND

Coxiellosis is a neglected zoonosis for occupationally exposed people in many parts of the world. Sheep and goats are two important small ruminants that act as reservoirs for human contamination; however, there is a lack of comprehensive data on the epidemiological aspects of coxiellosis in sheep and goats at regional and global levels. The aim of this study was to systematically review the available articles on seroprevalence of coxiellosis in sheep and goats and estimate the overall seroprevalence in different regions.

METHODS

A systematic search strategy was performed in five electronic repositories for articles published until December 2021. Relevant data were extracted from the selected articles based on the inclusion criteria. A random effect meta-analysis model was used to analyse the data. Results are presented as the prevalence of seropositivity as a percentage and 95% confidence intervals.

RESULTS

The global pooled seroprevalence of coxiellosis in sheep was 17.38% (95% confidence interval [CI]: 15.59%-19.17%). Overall, the regional level pooled prevalence estimates in sheep ranged from 15.04% (95% CI: 7.68%-22.40%) to 19.14% (95% CI: 15.51%-22.77%), depending on region. The global pooled seroprevalence of coxiellosis in goats was 22.60% (95% CI: 19.54%-25.66%). Overall, the regional level pooled prevalence estimates in goats ranged from 6.33% (95% CI: 2.96%-9.71%) to 55.13% (95% CI: 49.61%-60.65%), depending on the region. The prevalence estimates also varied significantly in both sheep and goats depending on age, sex, and rearing systems of the animals (p < 0.001).

CONCLUSION

Seroprevalence of coxiellosis in both sheep and goats is considerable. Routine monitoring of the sheep and goat populations is needed to prevent spillover infection in other livestock and humans.

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.

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.

Molecular detection of Coxiella burnetii in Kope cheese and cattle milk in West Azerbaijan, Iran

There are few studies on Coxiella burnetii (Cb) as a causative agent of Q fever in dairy products in Iran. The prevalence of Cb was studied by polymerase chain reaction (PCR) method in Kope (pot) cheese and cattle milk collected from West Azerbaijan province, Iran. A total number of 240 Kope cheese and 560 milk samples were collected during the year 2020. All samples were subjected to PCR based on transposable gene IS1111. The results showed that 12.50% (95.00% confidence interval (CI): 9.00 - 16.10%) of Kope cheese and 13.00% (95.00% CI: 10.00 - 17.30%) of milk samples were positive for Cb. There was a significant difference in cheese and milk contaminations with Cb among the defined age groups as well as regional and seasonal variations. It was concluded that Kope cheese and cattle milk are important sources of Cb and should be considered as important risk factors in the epidemiology of Q fever disease in public health.

Seroprevalence of Q Fever and Risk Factors Affecting Transmission of Coxiella burnetii in Industrial Slaughterhouse; A Survey from Northeastern Iran

Background: Q fever is a generally neglected infection caused by Coxiella burnetii. Slaughterhouse workers exposed to livestock are among occupationally at-risk people. Objectives: This study was conducted to investigate the seroprevalence of anti-Coxiella burnetii (Q fever) IgG antibody among industrial slaughterhouse workers and factors affecting the risk of infection. Methods: In this cross-sectional study serum samples were taken from 91 individuals working at the central industrial abattoir in Mashhad, Iran using a convenient sampling method. Sera were kept at -80°C until assayed for specific anti-Coxiella burnetii IgG antibodies (phase 1) using the commercial ELISA kit. The participants filled out a checklist addressing potential risk factors of acquiring the infection. SPSS 11.5 was used for data analysis considering a significance level of P < 0.05. Results: The participants’ mean age was 38.7 ± 8 years. Fifty-six percent of the studied individuals (51 out of 91) were found positive for anti-Coxiella burnetii antibodies. The most prevalent cases were sheep (29, 57%) and cow (18, 35%) butchers. The odds of Q fever infection increased among those with a history of accidental hand cuts of more than five times during the previous years (OR = 2.56, CI95% = 1.02 - 6.33, P-value = 0.04) and those dealing with sheep as the primary livestock (OR = 2.9, CI95% = 1.09 - 7.66, P = 0.02). Conclusions: The high seropositivity rate of anti-Coxiella burnetii IgG reflects high exposure rate of workers to this potentially serious pathogen in slaughtherhouses; therefore, careful education, follow-up, and revision of decontamination policies and improved occupational care and environmental hygiene should be strictly implemented in slaughterhouses to reduce the risk.

Seroepidemiological survey of brucellosis and Q fever among high-risk occupations in northeast of Iran for first time

Background and Objectives:

Brucellosis and Q fever are considered as occupational hazards to people in contact with domestic animals or their carcasses. The present cross-sectional study was carried out to determine the seroprevalence of brucellosis and Q fever among professions at risk in the North Khorasan Province, northeastern Iran during 2020.

Materials and Methods:

In this study, 185 sera samples were collected from butchers, slaughterhouse workers, farmers, and veterinarians in different counties of the province. The collected sera were tested by ELISA test for the detection of IgG antibodies against Coxiella burnetii and Brucella spp. A questionnaire was filled for each participant to investigate demographic characteristics information (i.e., age, gender, educational status, occupation, years of occupational experience, and location), and any exposure to risk factors (animals Keeping, consumption of unpasteurized dairy products, exposure to ill or dead animals, tick bite, splashing animal fluids, travel history, and use of personal protective equipment) that could be associated with these infections.

Results:

The seroprevalence of antibodies against C. burnetii and Brucella spp. were 17.2% and 19.4%, respectively. Twelve participants also had Q fever and brucellosis co-infection, with a prevalence of 6.4%.

Conclusion:

Based on the results, it is concluded that brucellosis and Q fever occur among the high-risk populations in this area and it needs more surveillance to control the diseases by public health and veterinary authorities.

A Review on Important Zoonotic Bacterial Tick-Borne Diseases in the Eastern Mediterranean Region

Background

Zoonotic diseases as health concerns worldwide account for more than half of the emerging infectious diseases. Arachnids are powerful vectors to transmit several diseases to humans. Additionally, these emerging zoonotic diseases have been a considerable health threat in the Eastern Mediterranean Region of the WHO (EMRO) due to the large population living close to farms and international trade with nearby countries.

Methods

This review study is based on the reported three tick-borne diseases, Lyme disease, Tularemia, and Q fever, from Iran and other EMRO countries. To this end, we searched PubMed central, ISI web of Science, and Google with the related keywords in English at any time. The reported data are then sorted by countries for each disease.

Results

According to the published data, 15 countries in the region have one/more emerging infectious diseases. Q fever has been the most frequent infection in EMRO countries, while Lyme was less recorded. Furthermore, Iran is among the countries with documented history of all three investigated diseases.

Conclusion

Tick-borne disease is popular among EMRO countries, indicating that they have natural conditions for infections in animals and humans. It appears necessary to develop a disease management strategy and control programs against tick-borne diseases (TBDs). Moreover, the disease-resistant animal could be bred instead of susceptible livestock. Therefore, research studies to control TBDs should be regarded as a top priority plan.

Sero-epidemiology investigation of Coxiella burnetii in domestic ruminants throughout most Greek regions

Q fever is not considered as a public health problem in Greece where most regions are considered as Coxiella burnetii free possibly because of the low interest for this agent. Our objective was to conduct a large‐scale study to investigate the sero‐epidemiology of C. burnetii in domestic ruminants throughout the most of Greek regions. We tested serum samples obtained from goats, sheep and bovines from different regions of Greece. All sera were tested for C. burnetii IgG antibodies by a commercial ELISA according to the manufacturer's recommendations. We tested 1,173 goats and sheep obtained from 177 different herds and totally 194 (17%) animals from 78 (44%) herds were positive for C. burnetii. Positive animals were present in seven (88%) different regions and seropositivity varied widely among these regions. The highest percentage was observed in Peloponnese (44%), where all the tested herds presented animals with C. burnetii antibodies. Ιn all Aegean Islands except the island of Limnos we detected goats and sheep positive for C. burnetii with seroposivity varying between 2% in Kos to 37% in Rhodes. Finally, in 22 (85%) Greek prefectures we found C. burnetii IgG‐positive animals whereas in 14 (54%) prefectures more than 50% of tested herds had seropositive animals. We also tested 28 cows from five different herds in Macedonia and Aegean Islands and six (21%) of them, obtained from two (40%) herds were positive. Considering the importance of C. burnetii for public health, our data reflect the lack of awareness by veterinarians, physicians and competent authorities as we provide evidence of C. burnetii seropositivity in productive animals throughout the most of Greek territories. Due to the increased risk of inhalation of the bacterium by people who entered the affected farms we raise the question of Q fever emergence in Greece.

Preparedness of community-based organisations in biohazard: reliability and validity of an assessment tool

The purpose of this study was to develop a tool for community-based health organisations (CBHOs) to evaluate the preparedness in biohazards concerning epidemics or bioterrorism. We searched concepts on partnerships of CBHOs with health systems in guidelines of the Centers for Disease Control and Prevention and literature. Then, we validated the researcher-made tool by face validity, content validity, exploratory factor analysis (EFA), confirmatory factor analysis (CFA) and criterion validity. Data were collected by sending the tool to 620 CBHOs serving under supervision of Iran’s ministry of health. Opinions of health professionals and stakeholders in CBHOs were used to assess face and content validity. Factor loads in EFA were based on three-factor structure that verified by CFA. We used SPSS V.18 and Mplus7 software for statistical analysis. About 105 health-based CBHOs participated. After conducting face validity and calculating content validity ratio and content validity index, we reached 54 items in the field of planning, training and infrastructure. We conducted construct validity using 105 CBHOs. Three items exchanged between the fields according to factor loads in EFA, and CFA verified the model fit as Comparative Fit Index, Tucker-Lewis index and root mean square error of approximation were 0.921, 0918 and 0.052, respectively. The Cronbach’s of the whole tool was 0.944. Spearman correlation coefficient confirmed criterion validity as coefficient was 0.736. Planning, training and infrastructure fields are the most important aspects of preparedness in health-based CBHOs. Applying the new assessment tool in future studies will show the weaknesses and capabilities of health-based CBHOs in biohazard and clear necessary intervention actions for health authorities.

Seroepidemiological study of Q fever, brucellosis and tularemia in butchers and slaughterhouses workers in Lorestan, western of Iran

Most zoonoses are occupational diseases. Q fever, brucellosis and tularemia are major zoonotic diseases for butchers and slaughterhouse workers. However, little information is available about these infectious diseases in such professional populations in western of Iran. The aim of this study was to investigate the seroprevalence and risk factors associated with these three zoonoses among butchers and slaughterhouse workers in the Lorestan province of Iran. In 2017, 289 individuals (144 butchers or slaughterhouse workers, and 145 people from the general population) were enrolled in 11 different counties of this province. Collected serum samples were tested by ELISA for detection of IgG antibodies against Coxiella burnetii, Brucella spp. or Francisella tularensis antigens. The seroprevalence of Q fever, brucellosis and tularemia among all participants were 23.5%, 31.8% and 3.8%, respectively. The seroprevalence of brucellosis and Q fever among butchers and slaughterhouse workers (43.7% and 29.8%, respectively) were significantly higher (p < 0.05) than those of the general population (20% and 17.2%, respectively). A contact history with small ruminants (sheep and goats) was associated with a higher risk of positive serology for all three studied zoonoses. The high seroprevalence for Q fever and brucellosis we found among butchers and slaughterhouse workers suggests that both diseases are common in these populations of the Lorestan province. Since these two infectious diseases are clinically unspecific, they must be systematically included in the etiological diagnosis of infectious diseases occurring in these at-risk populations. In addition, we recommend specific training programs as well as the use of personal protective equipment in these occupational groups to reduce the occurrence of these zoonotic diseases.

Prevalence of Coxiella burnetii in unpasteurized dairy products using nested PCR assay

BACKGROUND AND OBJECTIVES

Q fever is a worldwide disease which is common between humans and livestock. This disease is created by an obligate intracellular Rickettsia called Coxiella burnetii (C. burnetii). The aim of this study was to determine the prevalence of C. burnetii in unpasteurized dairy products in Shiraz.

MATERIALS AND METHODS

In this study (from summer 2016 to winter 2016), 238 non-pasteurized dairy products, (48 raw milk, 48 yogurt, 46 cheese, 48 dough and 48 ice cream samples) were collected from the retail market and analyzed using a nested PCR assay.

RESULTS

This study showed that 20 samples (8.4%), out of the 238 unpasteurized dairy products, were positive for C. burnetii as follows: 13 out of 48 (27.08%) raw milk, 3 out of 48 (6.25%) yogurt, 2 out of 46 (4.35%) cheese, 2 out of 48 (4.16%) dough, and 0 out of 48 ice cream samples.

CONCLUSION

The present study suggests that unpasteurized dairy products are the main sources of C. burnetii in Shiraz, Southern Iran; thus, the consumption of pasteurized milk and dairy products is a valuable method to prevent the disease in humans.