Ocular Toxocariasis: Beyond Typical Patterns through the New Imaging Technologies

Ocular Toxocariasis in Adult Caucasian Patients: Clinical Presentations and Treatment Outcomes

PURPOSE

To report the clinical features and treatment outcomes in adult Caucasians with ocular toxocariasis (OT) and investigate their prognosis depending on their serological status.

METHODS

Retrospective observational cohort study (2016-2021) including consecutive adults with uveitis and positive western blot (WB) in the aqueous humor or vitreous. The presence of serum antibodies was not necessary for inclusion, allowing to compare the outcomes depending on the serological status.

RESULTS

Seventeen eyes of 15 patients were included. Mean age at diagnosis was 51.9 years. Vitreous inflammation was the most frequent sign (100%). Vitreoretinal tractions (41.2%) and chorioretinal granulomas (58.8%) were less prevalent. Atypical features were: spontaneous intravitreal hemorrhage (23.5%), exudative retinal detachment (11.8%), isolated macular edema (17.6%), papillitis (29.4%) and vasculitis (47.1%). Twenty percent of patients had a positive serum serology. Baseline clinical features did not differ statistically depending on the serological status; however, the degree of inflammation was numerically higher in patients with negative serology. Overall, macular thickness, anterior and posterior segment inflammation improved significantly after treatment with oral albendazole, systemic ± local corticosteroids. Vitrectomy (47.1%) was performed in case of persistent vitritis (62.5%), retinal detachment (12.5%) and intravitreous hemorrhage (25%).

CONCLUSION

OT has no pathognomonic sign and atypical presentations were not infrequent in this adult Caucasian cohort. Serum antibodies were rarely positive, stressing on the importance of ocular sample analysis, especially in case of atypical features. Serum antibodies may prove useful in forecasting the rapidity of inflammation clearance. Antiparasitic and anti-inflammatory treatment was safe and efficient in most cases.

The Consistency of Anti-Toxocara IgG Between the Aqueous Humor and Vitreous of Patients With Clinically Suspected Ocular Toxocariasis

PURPOSE

To assess the consistencies of anti-Toxocara IgG (T-IgG) and Goldmann-Witmer coefficient (GWC) between paired aqueous humor (AH) and vitreous samples from patients with clinically suspected ocular toxocariasis (OT).

DESIGN

Inter-test reliability assessment.

METHODS

A total of 47 patients with clinically suspected OT who underwent vitrectomy were included. AH, vitreous, and serum samples from each patient were collected, and levels of specific T-IgG in them were detected. The association and agreement of T-IgG and GWC between AH and vitreous were evaluated. The area under the receiver operating characteristic curve was generated to assess the diagnostic performance of AH.

RESULTS

The T-IgG levels and GWC values in vitreous were higher than those in AH (P = .023 and P = .029, respectively), but similar positivity rates in the T-IgG (P = 1.000) and GWC >3 (P = 1.000) were apparent between vitreous and AH. In addition, there was a positive correlation between the AH and vitreous T-IgG levels (rs = 0.944, P < .001) and the GWC values (rs = 0.455, P = .022). Moreover, the consistencies between AH and vitreous samples in their T-IgG and GWC positivity rates were almost perfect (both, κ = 0.915, 95% CI = 0.799-1.000) in both. The area under the receiver operating characteristic curve reached 0.991, with a 95% confidence interval of 0.971 to 1.000. The best cut-off value for accurate OT diagnosis was found at 1.434, yielding 96% sensitivity and 100% specificity.

CONCLUSIONS

Our findings demonstrate that AH and vitreous samples had significant correlations and perfect agreements for both T-IgG and GWC, suggesting that the AH may serve as a proxy for vitreous to provide a safer, earlier, and more convenient screening of OT.

Understanding the research and practical needs required to control toxocariasis in Iran

Human toxocariasis (HT) is a widespread zoonotic infection globally, notably prevalent in tropical areas. Enhancing our understanding of toxocariasis can lead to increased attention towards the socioeconomic impact and control of this neglected zoonosis. We conducted a comprehensive review of all available articles and official documents on toxocariasis in Iran to identify research gaps and critical needs for its control. This review highlights that despite numerous studies exploring various aspects of toxocariasis in definitive and paratenic hosts, as well as humans and environmental contamination, significant data deficiencies and gaps persist across different regions in the country. These gaps involve investigating the worm burden and reinfection rates in definitive hosts, developing more sensitive methods to detect and differentiate of Toxocara species, and understanding the behavior of definitive host animals. Additionally, identifying potential paratenic hosts for HT and exploring the organ-specific affinity and survival duration of Toxocara larvae within these hosts are essential areas for exploration. It's also imperative to comprehend the sylvatic and domestic cycles of the parasite in paratenic hosts. Furthermore, assessing egg density in the environment, exploring potential new sources such as water, and identifying regions with optimal climatic conditions for the survival and development of Toxocara eggs are crucial for the formulation of effective prevention and control strategies. Identifying at-risk groups, developing early diagnosis techniques, employing imaging methods, and identifying long-term complications in humans are also crucial. Community health organizations should prioritize health education for the public and professionals. Furthermore, accurately estimating definitive host populations, monitoring and preventing their movements in public places, implementing regular deworming practices for pets and stray hosts, and recognizing the infection's significance as a health priority are critical. This comprehensive understanding advocates for a holistic "one health" approach to control of HT.

Pediatric Posterior Infectious Uveitis

PURPOSE

To describe the most important cause of infectious posterior uveitis in pediatric patients.

METHODS

Review of the literature.

RESULTS

The most important causes of infectious uveitis in pediatric patients are: cat-scratch disease, toxocariasis, tuberculosis, viral diseases and toxoplasmosis. Ocular manifestations include retinitis, neuroretinitis, choroidal granulomas, peripheral granulomas and posterior pole granulomas.

CONCLUSION

Infectious posterior uveitis is a challenging subject and should be considered in the differential diagnosis of any posterior uveitis in children. Infectious uveitis must be excluded before initiating immunosuppressive therapy.

Live Larva in Ocular Toxocariasis

This case report describes a finding of a live larva in a patient with a previous diagnosis of ocular toxocariasis.