Meta-analysis is a method to obtain a weighted average of results from various studies. In addition to pooling effect sizes, meta-analysis can also be used to estimate disease frequencies, such as incidence and prevalence. In this article we present methods for the meta-analysis of prevalence. We discuss the logit and double arcsine transformations to stabilise the variance. We note the special situation of multiple category prevalence, and propose solutions to the problems that arise. We describe the implementation of these methods in the MetaXL software, and present a simulation study and the example of multiple sclerosis from the Global Burden of Disease 2010 project. We conclude that the double arcsine transformation is preferred over the logit, and that the MetaXL implementation of multiple category prevalence is an improvement in the methodology of the meta-analysis of prevalence.

Meta-analysis of prevalence

Background Echinococcosis (canine Echinococcus disease) is a neglected tropical disease that causes serious public harm Dogs, as a terminal host of Echinococcus spp, are a key part of the Echinococcus epidemic Echinococcosis spreads easily in humans and animals in some areas of China and it is therefore necessary to fully understand the prevalence of Echinococcus spp in dogs Methodology/principal findings PubMed, ScienceDirect, Chongqing VIP, China National Knowledge Infrastructure (CNKI), and WanFang databases were searched for relevant articles published in the past 10 years A final total of 108 studies were included The overall prevalence of Echinococcus spp in dogs in China was 73%, with the highest point estimate found in sampling year 2015 (82%) and publication year 2015 (165%) Northwestern China (79%) had the highest infection rate in China Qinghai Province (135%) showed the highest prevalence among the 11 provinces we included We also found that geographical and climatic factors are related to the incidence of canine echinococcosis We further investigated the source of heterogeneity by analysis of subgroups (sampling district, detection method, dog type, season, parasite species, medication, and study quality level) Conclusions/significance Our research indicated that Echinococcus spp were still prevalent in some areas in China More localized prevention and control policies should be formulated, including improving drinking water hygiene and strengthening hygiene promotion We recommend the rational use of anti-Echinococcus drugs In addition, treatment of livestock offal and feces and improving the welfare of stray dogs may play an important role in reducing canine Echinococcus infections

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Meta-analysis of the prevalence of Echinococcus in dogs in China from 2010 to 2019.

Toxoplasma gondii infections are common in humans and animals worldwide. The ingestion of food or water contaminated with oocysts excreted by infected cats or ingesting uncooked or undercooked meat containing tissue cysts of T. gondii are the 2 major modes of transmission of T. gondii. Viable T. gondii is more prevalent in pork and lamb than in beef. In the past decade, there have been many articles on the high seroprevalence in cattle, particularly from China. There is a report of an outbreak of acute toxoplasmosis in humans suspected to be linked to the ingestion of Artisan fresh cheese from cow's milk. There are conflicting reports concerning the rate of congenital transmission of T. gondii in cattle, especially from Brazil. In a report from Brazil, viable T. gondii was isolated from the blood of 1 of 60 pregnant cows slaughtered at an abattoir and from 1 fetus. The role of beef in the epidemiology of T. gondii infections is still not clear. Here, we review prevalence, persistence of infection, clinical disease, epidemiology, and public health risks of T. gondii infections in cattle from beef and cow's milk worldwide for the past decade.

https://bioone.org/journals/journal-of-parasitology/volume-106/issue-6/20-82/Public-Health-Significance-of-Toxoplasma-gondii-Infections-in-Cattle/10.1645/20-82.pdf

Public Health Significance of Toxoplasma gondii Infections in Cattle: 2009–2020

The global prevalence and risk factors of Toxoplasma gondii among foxes: A systematic review and meta-analysis.

BackgroundToxoplasmosis is caused by Toxoplasma gondii which can infect all warm-blooded animals. As the most common feline definitive host, cats play a vital role in the transmission of T. gondii. However, national estimates of the seroprevalence of T. gondii in cats in mainland China are lacking, and therefore a systematic review and meta-analysis were performed to provide insight into national environmental transmission levels and potential transmission to humans.MethodsStudies published up until July 1, 2016, on T. gondii seroprevalence in cats within mainland China were searched for in CNKI, WanFang, CBM, PubMed, Embase and through the reference lists of resulting articles. The seroprevalence with its 95% confidence interval (CI) for each individual study was presented, and then point estimates and their 95% confidence intervals (CIs) of pooled seroprevalence were calculated. Subgroup analyses were performed according to potential risk factors.ResultsA total of 38 eligible studies, published between 1995 to 2016, covering fifteen provinces and municipalities, and involving 7,285 cats, were included. The seroprevalence in cats per study ranged from 3.9 to 79.4% with a median of 20.3%. As substantial heterogeneity existed among studies, a random-effects model was used to estimate the pooled seroprevalence. The value of the point estimate seroprevalence was 24.5% (95% CI: 20.1–29.0). Seroprevalence in stray cats was significantly higher than in pet cats (OR = 3.00, 95% CI: 1.60–5.64). The seroprevalence increased significantly with cat age (P = 0.018) with 17.4% (95% CI: 7.6–27.2) in the group of ≤ 1 year old, 19.5% (95% CI: 12.7–26.3) in the group of ≤ 3 year-old and 31.6% (95% CI: 22.9–40.3) in the group of > 3 year-old.ConclusionsThe seroprevalence of T. gondii in cats in mainland China was moderate and was associated with cat ownership and age. Due to the increasing prevalence of pet cats in China and the intimate relationship between these cats and humans, this might present a significant exposure risk, particularly for China’s large susceptible population. Therefore, further research is needed into the links between cat ownership and human T. gondii infection and how to reduce T. gondii exposure in humans via cat contacts and the environmental contamination with T. gondii oocysts by cats.

Jiao Li

Papers

Seroprevalence of Toxoplasma gondii in cattle in China from 2010 to 2019: A systematic review and meta-analysis.