This article is more than 5 years old. Information may no longer be current.

Toxocara species positivity associated with asthma

There was a significant positive association found between patients with asthma and the prevalence of Toxocara species seropositivity in recent study results.

“Human toxocariasis is a cosmopolite helminthic zoonosis caused by Toxocara canis and Toxocara cati, which are common roundworms of dogs and cats, respectively,” Lingling Li, MD, department of respiratory medicine, The First Affiliated Hospital of Nanjing Medical University, China, and colleagues reported.

The researchers conducted a literature search of PubMed, Embase and Web of Science from inception through Oct. 1, 2013. Key search terms were used for asthma and toxocariasis. Titles, abstracts and full articles were reviewed by two independent investigators. A random-effects meta-analysis model of aggregated published data was used.

Of 632 studies reviewed, 10 studies with 1,530 participants (723 patients with asthma, 807 controls) were included in the meta-analysis. There was a significant association between Toxocara exposure and asthma in seven studies.

A significantly higher prevalence of Toxocara speciesinfection was found in patients with asthma compared with controls (OR=3.36; 95% CI, 1.76-6.42). When studies were restricted to only children (OR=2.8; 95% CI, 1.35-5.82) or adults (OR=5.96; 95% CI, 1.62-21.83), the significance was similar.

“A positive association between Toxocara species seropositivity and asthma has been shown found, although it does not confirm the causal relation,” the researchers concluded. “It indicates a need to enforce methods of control and preventive measures against Toxocara infection.

“More studies that include larger populations, standardized serologic assays and statistical analyses are required to clarify the association between Toxocara species and asthma. Further investigations … are needed to understand the relation between Toxocara infection and asthma.”

Disclosure: The researchers report no relevant financial disclosures.