Global status of Anaplasma phagocytophilum infections in human population: A 50-year (1970-2020) meta-analysis.

BACKGROUND & OBJECTIVES: Anaplasma phagocytophilum causes human granulocytic anaplasmosis; a febrile tick-borne bacterial zoonosis of increasing public health importance in many parts of the world which is life threatening in undiagnosed, misdiagnosed and untreated cases. In this study we determined and reported the global status of the pathogen in man. METHODS: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was used to perform a systematic review and meta-analysis of data published in six electronic databases between 1970 and 2020. We pooled data using the random-effects model, performed sensitivity analysis by the single study deletion method and assess across study bias by the funnel plot and its statistical significance by the Egger's regression test. RESULTS: A total of 7018 cases of A. phagocytophilum were reported from 48,619 individuals examined across 22 countries in three continents. Overall pooled estimate was 8.13% (95% CI: 5.70 - 11.47) with a range of 4.64 (95% CI: 1.78 - 11.54) to 12.18% (95% CI: 7.66 - 18.83) across sub-groups. Regional prevalence was highest in North America 11.07% (95% CI: 3.13 - 32.38), while that in relation to study population was highest among occupationally exposed population 11.41% (95% CI: 5.69 - 21.56). INTERPRETATION & CONCLUSION: The study revealed a significant variation in the prevalence of A. phagocytophilum across Asia, Europe and North America, with the highest prevalence in North America and among occupationally exposed population. To curtail the menace of this growing public health crisis, we recommend integrated control programmes involving tick control, the use of appropriate clothing by occupationally exposed population and health education.

Worldwide meta-analysis on Anaplasma phagocytophilum infections in animal reservoirs: Prevalence, distribution and reservoir diversity.

A wide range of vertebrate species are competent reservoirs of Anaplasma phagocytophilum, where the pathogen is maintained in the enzootic cycle and transmitted to humans through activities of tick vectors. An insight into the role and diversity of these reservoirs is vital in understanding the epidemiology of this pathogen. Here, we determined the prevalence, distribution and reservoir diversity of A. phagocytophilum using a systematic review and meta-analysis. Data pooling was performed by the random-effects model, heterogeneity was assessed by the Cochran's Q-test and publication bias by Egger's regression test. Eighty-nine studies from 33 countries across 5 continents revealed A. phagocytophilum pooled prevalence of 15.18% (95% CI: 11.64, 19.57). Continental estimates varied significantly (p < 0.0001), with a range of 2.88% (95% CI: 0.25, 26.20) in South America to 19.91% (95% CI: 13.57, 28.24) in Europe. Country-based estimates ranged between 2.93% (95% CI: 1.17, 7.16) in Slovakia and 71.58% (95% CI: 25.91, 94.77) in Norway. Studies on A. phagocytophilum were concentrated in Europe (51.69%; 46/89) by continent and the USA (22.47%; 20/89) by country. Prevalence in wildlife (17.64%; 95% CI: 12.21-28.59) was significantly higher (p < 0.001) than that among domestic animals (10.68%; 95% CI: 6.61-16.83). Diverse species of wildlife, domestic animals and birds were infected by A. phagocytophilum. To curtail the public health, veterinary and economic consequences of A. phagocytophilum infections, we recommend an all-inclusive epidemiological approach that targets the human, animal and environmental components of the disease.

Africa-wide meta-analysis on the prevalence and distribution of human cystic echinococcosis and canine Echinococcus granulosus infections.

BACKGROUND: Echinococcosis is a neglected zoonosis of increasing public health concern worldwide. According to the World Health Organization, 19,300 lives and 871,000 disability-adjusted life-years are lost globally each year because of cystic echinococcosis. Annual costs associated with cystic echinococcosis were estimated at US$ 3 billion because of treatment of cases and losses in the livestock industry. METHODS: We performed the random-effects model of meta-analysis using 51-year (1970-2021) data available from AJOL, Google Scholar, PubMed, Science Direct, Scopus and Web of Science. We also applied the Joanna Briggs Institute critical appraisal instrument for studies reporting prevalence data, the Cochran's Q-test, Egger's regression test and the single study deletion technique to respectively examine within-study bias, heterogeneity, across-study bias and sensitivity. RESULTS: Thirty-nine eligible studies on human cystic echinococcosis (HCE) from 13 countries across the five African sub-regions showed an overall prevalence of 1.7% (95% CI 1.1, 2.6) with a statistically significant (P < 0.001) sub-group range of 0.0% (95% CI 0.0, 14.1) to 11.0% (95% CI 7.6, 15.7). Highest prevalences were observed in Eastern Africa (2.7%; 95% CI 1.4, 5.4) by sub-region and Sudan (49.6%; 95% 41.2, 58.1) by country. Another set of 42 studies on Echinococcus granulosus infections (EGI) in dogs from 14 countries across the five African sub-regions revealed an overall prevalence of 16.9% (95% CI 12.7, 22.3) with a significant (P < 0.001) variation of 0.4 (95% CI 0.0, 5.9) to 35.8% (95% CI 25.4, 47.8) across sub-groups. Highest prevalences of E. granulosus were observed in North Africa (25.6%; 95% CI 20.4, 31.6) by sub-region and Libya (9.2%; 95% CI 5.7, 13.9) by country. CONCLUSION: Human cystic echinococcosis and EGI are respectively prevalent among Africans and African dogs. We recommend a holistic control approach that targets humans, livestock, dogs and the environment, which all play roles in disease transmission. This approach should involve strategic use of anthelminthics in animals, standardized veterinary meat inspection in abattoirs, control of stray dogs to reduce environmental contamination and proper environmental sanitation. Mass screening of humans in hyper-endemic regions will also encourage early detection and treatment.

Anaplasma phagocytophilum infection rates in questing and host-attached ticks: a global systematic review and meta-analysis.

Anaplasma phagocytophilum causes a multi-organ non-specific febrile illness referred to as human granulocytic anaplasmosis. The epidemiologic risk of the pathogen is underestimated despite human encroachment into the natural habitats of ticks. In this study, we performed a systematic review and meta-analysis to determine the global infection rates and distribution of A. phagocytophilum in tick vectors. We pooled data using the random-effects model, assessed individual study quality using the Joanna Briggs Institute critical appraisal instrument for prevalence studies and determined heterogeneity and across study bias using Cochran's Q-test and Egger's regression test respectively. A total of 126 studies from 33 countries across 4 continents reported A. phagocytophilum estimated infection rate of 4.76% (9453/174,967; 95% CI: 3.96, 5.71). Estimated IRs across sub-groups varied significantly (p <0.05) with a range of 1.95 (95% CI: 0.63, 5.86) to 7.15% (95% CI: 5.31, 9.56). Country-based IRs ranged between 0.42 (95% CI: 0.22, 0.80) in Belgium and 37.54% (95% CI: 0.72, 98.03) in Norway. The highest number of studies on A. phagocytophilum were in Europe (82/126) by continent and the USA (33/126) by country. The risk of transmitting this pathogens from ticks to animals and humans exist and therefore, we recommend the use of chemical and biological control measures as well as repellents and protective clothing by occupationally exposed individuals to curtail further transmission of the pathogen to humans and animals.

Infection rates, species diversity, and distribution of zoonotic Babesia parasites in ticks: a global systematic review and meta-analysis.

Zoonotic Babesia species are emerging public health threats globally, and are the cause of a mild to severe malaria-like disease which may be life threatening in immunocompromised individuals. In this study, we determine the global infection rate, distribution, and the diversity of zoonotic Babesia species in tick vectors using a systematic review and meta-analysis. We used the random-effects model to pool data and determined quality of individual studies using the Joanna Briggs Institute critical appraisal instrument for prevalence studies, heterogeneity using Cochran's Q test, and across study bias using Egger's regression test. Herein, we reported a 2.16% (3915/175345, 95% CI: 1.76-2.66) global infection rate of zoonotic Babesia species (B. divergens, B. microti, and B. venatorum) in tick vectors across 36 countries and 4 continents. Sub-group infection rates ranged between 0.65% (95% CI: 0.09-4.49) and 3.70% (95% CI: 2.61-5.21). B. microti was the most prevalent (1.79%, 95% CI: 1.38-2.31) species reported in ticks, while Ixodes scapularis recorded the highest infection rate (3.92%, 95% CI: 2.55-5.99). Larvae 4.18% (95% CI: 2.15-7.97) and females 4.08% (95% CI: 2.56-6.43) were the tick stage and sex with the highest infection rates. The presence of B. divergens, B. microti, and B. venatorum in tick vectors as revealed by the present study suggests possible risk of transmission of these pathogens to humans, especially occupationally exposed population. The control of tick vectors through chemical and biological methods as well as the use of repellants and appropriate clothing by occupationally exposed population are suggested to curtail the epidemiologic, economic, and public health threats associated with this emerging public health crisis.

Global meta-analysis on Babesia infections in human population: prevalence, distribution and species diversity.

Human babesiosis is an emerging tick-borne protozoan zoonosis caused by parasites of the genus Babesia and transmitted by ixodid ticks. It was thought to be a public health problem mainly for the immunocompromised, however the increasing numbers of documented cases among immunocompetent individuals is a call for concern. In this systematic review and meta-analysis, we reported from 22 countries and 69 studies, an overall pooled estimate (PE) of 2.23% (95% CI: 1.46-3.39) for Babesia infections in humans. PEs for all sub-groups varied significantly (p < 0.05) with a continental range of 1.54% (95% CI: 0.89-2.65) in North America to 4.17% (95% CI: 2.11-8.06) in Europe. PEs for country income levels, methods of diagnosis, study period, sample sizes, Babesia species and targeted population ranged between 0.43% (95% CI: 0.41-0.44) and 7.41% (95% CI: 0.53-54.48). Babesia microti recorded the widest geographic distribution and was the predominant specie reported in North America while B. divergens was predominantly reported in Europe. Eight Babesia species; B. bigemina, B. bovis, B. crassa-like, B. divergens, B. duncani, B. microti, B. odocoilei and B. venatorum were reported in humans from different parts of the world with the highest prevalence in Europe, lower middle income countries and among individuals with history of tick bite and other tick-borne diseases. To control the increasing trend of this emerging public health threat, tick control in human settlements, the use of protective clothing by occupationally exposed people and the screening of transfusion blood in endemic countries are recommended.Abbreviations AJOL: African Journals OnLine, CI: Confidence interval, CIL: Country income level, df: Degree of freedom, HIC: Higher-income countries, HQ: High quality, I2: Inverse variance index, IFAT: Indirect fluorescent antibody test, ITBTBD: Individuals with tick-bite and tick-borne diseases, JBI: Joanna Briggs Institute, LIC: Lower-income countries, LMIC: Lower middle-income countries, MQ: Medium quality, NA: Not applicable, N/America: North America, OEI: Occupational exposed individuals, OR: Odds ratio, PE: Pooled estimates, PCR: Polymerase chain reaction, Prev: Prevalence, PRISMA: Preferred Reporting System for Systematic Reviews and Meta-Analyses, Q: Cochran's heterogeneity statistic, QA: Quality assessment, Q-p: Cochran's p-value, qPCR: Quantitative polymerase chain reaction, S/America: South America, Seq: Sequencing, UMIC: Upper middle-income countries, USA: United States of America.