[Congenital ocular toxocariasis in a premature neonate]

The Red Reflex Test and Leukocoria in Childhood

The red reflex test, performed using a direct ophthalmoscope, serves as a critical diagnostic tool in identifying various ocular conditions. These conditions encompass retinal anomalies (such as retinoblastoma, Coats disease, retinopathy of prematurity, familial exudative vitreoretinopathy, myelinated nerve fibers, ocular toxocariasis, ocular toxoplasmosis, retinochoroidal coloboma, astrocytic, and combined hamartoma), vitreous abnormalities (including persistent fetal vasculature), lens issues (like cataract), anterior chamber and corneal conditions (comprising dysgenesis of the anterior segment, congenital glaucoma, birth trauma), and tear film disturbances. During this examination, the presence of leukocoria, characterized by a white pupillary reflex, can suggest the presence of underlying conditions. Any suspicion of an abnormal red reflex test warrants immediate evaluation by a qualified ophthalmologist. This article primarily underscores the paramount importance of the red reflex examination, not only to identify potential sight-threateningbut also life-threatening conditions. It delves into the most common causes of leukocoria in childhood and offers insights into a comprehensive diagnostic approach. The target audience for this article includes pediatricians, primary care clinicians, and ophthalmologists, all of whom play a pivotal role in the early detection and intervention of these critical eye disorders.

Serosurvey of Toxoplasma gondii and Toxocara spp. co-infection in pregnant women in low-income areas of Brazil

Introduction

Despite human toxoplasmosis and toxocariasis having been listed among the top six most neglected parasitic zoonoses worldwide, presenting similar associated risk factors and transmission routes, few studies have been conducted in pregnant women and the consequences of concurrent infection remain to be fully established. Accordingly, the present study has serologically assessed the co-infection and associated risk factors for Toxoplasma gondii and Toxocara spp. in pregnant women, assisted by the public Unified National Health System (SUS) in southeastern Brazil.

Materials and Methods

Blood samples were collected and tested for IgG antibodies against Toxoplasma gondii by chemiluminescence immunoassay and against Toxocara spp. by enzyme-linked immunosorbent assay (ELISA). An epidemiological questionnaire was applied to gather socioeconomic information to assess the risk factors associated with seropositivity to toxocariasis/toxoplasmosis by univariate analysis followed by logistic regression.

Results

Overall, seropositivity was 69/280 (24.6, 95% CI: 19.96-30.01) for T. gondii and 56/280 (20.0, 95% CI: 15.73-25.08) for Toxocara spp. Co-infection was observed in 25/280 (8.9, 95% CI: 6.12-12.85) pregnant women, with increased odds (OR: 3.3, CI 95%: 1.77-6.14, p = 0.0002). Logistic regression revealed that a higher educational level (high school or college) significantly reduced the likelihood of co-infection seropositivity, owning cats increased the odds of toxocariasis, and older pregnant women presented significantly higher T. gondii seropositivity.

Conclusion

Co-infection herein highlights the importance of educational programs in the prevention of toxocariasis and toxoplasmosis in pregnant women and other high-risk populations.

Risk factors for toxocariasis during incarceration: the One Health intervention approach

Despite potential exposure to soil-transmitted helminths, especially when stray dogs and cats are present, toxocariasis in inmate populations remains to be established. Accordingly, the present study assessed the seroprevalence and associated risk factors of toxocariasis at the Women's State Penitentiary of Parana, Brazil. A total of 234/370 (63.2%; 95% CI 58.2-68.0) women inmates and 28/87 (32.2%; 95% CI 23.3-42.6) correctional officers were seropositive for anti-Toxocara spp. IgG by ELISA, with inmates 2.62-fold more likely positive (p = 0.00000026). The univariate model has identified that non-white (OR = 1.58, p = 0.047) and older than 39 years (OR = 1.28, p = 0.032) inmates were associated with mild but significant odds for seropositivity. Elementary or higher educational level was considered a protective factor for seropositivity. The presence of Toxocara spp. eggs was observed in 10/15 (66.7%) collected soil samples by centrifuge-flotation in Zinc Sulfate, and molecular analysis by PCR identified only Toxocara cati in these eggs. An intervention program was established with regular trap-neuter-release, with gradual removal for adoption (donation campaigns), treatment, and euthanasia when necessary (particularly due to advanced sporotrichosis). In addition, an educational awareness agenda was proposed, aiming to reduce soil contamination and accidental intake by the incarcerated population. A total of 40 feral cats were trapped, 20 males and 20 females, mostly adults. After trapping, 36 cats were neutered, treated, and microchipped in the Veterinary Teaching Hospital (VTH) at the Federal University of Paraná. Five trapped feral cats were euthanized, four diagnosed with advanced sporotrichosis, and one already neutered cat (not herein) with complications due to feline immunodeficiency virus (FIV). Female inmates presented higher seroprevalence for Toxocara spp. antibodies when compared to correctional officers, significantly associated with age, self-declared ethnicity (non-white), and lack of formal education. Despite the non-natural scenario of a state penitentiary, the One Health approach of Toxocara spp. has highlighted the interdisciplinary nature of the study and its relevance in understanding the complex interactions between human, animal, and environmental factors, particularly impacting female inmates. Further studies should establish the rate of inmate infection over time while deprived of liberty.

Serosurvey of anti-Toxocara antibodies and risk factors in adolescent and adult pregnant women of southeastern Brazil

Toxocariasis is worldwide endemic parasitic anthropozoonosis with high risk to those in in vulnerable populations and particularly during pregnancy and childhood. Although the prevalence of anti-Toxocara spp. antibodies has been extensively studied, risk factors of pregnant women of different ages remains to be established. This study was designed to i) assess the presence of anti-Toxocara spp. antibodies in pregnant women that presented to the public health system in a city of southeastern Brazil, and ii) determine the risk factors for toxocariasis in adolescent and adult pregnant women. This cross-sectional study included 280 pregnant women (71 aged up to and including 17 years [adolescents] and 209 aged 18 years and older [adults]). Pregnant women voluntarily agreed to complete a socioeconomic questionnaire and provide serum samples. Anti-Toxocara IgG antibodies were screened by Enzyme-Linked Immunosorbent Assay (ELISA). Univariable and multivariable logistic regression models were performed to assess the risks for toxocariasis. Overall, 20.7% of pregnant women were seropositive (33.8% of adolescents and 16.3% of adults). Prevalence in pregnant adolescents was 2.6-fold higher than in adults (Odds ration [OR]: 2.63; 95% CI: 1.42-4.86, p = 0.003). Multivariate analysis revealed that contact with soil (p = 0.01; OR = 4.76) and being in the first trimester of pregnancy (p = 0.03; OR = 0.17) had significantly greater risk of toxocariasis for adolescents, and attainment of elementary through middle school education level (p = 0.05; OR = 8.33) was a risk factor in adult pregnant women. Toxocariasis is likely underreported and neglected in adolescent pregnant women; this age group should always be monitored for toxocariasis and correspondent clinical signs, particularly at late pregnancy.

A Rare Case of Congenitally Acquired Ocular Toxocariasis in A Five-Week-Old Infant

Purpose: To report a case of strabismus in a five-week-old infant, likely secondary to a rare occurrence of congenitally acquired ocular toxocariasis.Methods: Retrospective case report.Results: A five-week-old male infant with left exotropia was referred to pediatric ophthalmology and to a vitreoretinal specialist. Fundoscopic examination revealed a granuloma with associated retinal folds and tractional retinal detachment typical for ocular toxocariasis. Serology revealed positivity for Toxocara antibodies, consistent with the clinical diagnosis of ocular toxocariasis.Conclusion: Ocular toxocariasis is typically thought to be secondary to acquired Toxocara infection secondary to fecal-oral transmission. In this case of early-onset strabismus secondary to ocular toxocariasis, it is hypothesized that this is a presentation of congenitally acquired toxocariasis.

A prospective seroepidemiological study of toxocariasis during early childhood in coastal Ecuador: potential for congenital transmission and risk factors for infection

Background

Although Toxocara spp. infection has a worldwide distribution, to our knowledge, no data from birth cohorts have been reported in published studies on the potential for congenital transmission and determinants of infection in early childhood.

Methods

We followed 290 mother-infant pairs from birth to 5 years of age through periodic collection of data and samples at birth, 7 and 13 months and 2, 3 and 5 years of age. Data on potential risk factors and confounders were collected by maternal questionnaire. Blood for plasma was collected from the mother at time of birth and periodically from the child for detection of anti-Toxocara spp. immunoglobulin G (IgG) antibodies using a Toxocara canis larval excretory-secretory antigen-based enzyme-linked immunosorbent assay. Stool samples were collected from the mother around the time of birth and periodically from the child for microscopic detection of soil-transmitted helminths (STH). Associations between potential risk factors and Toxocara spp. seroprevalence and seroconversion were estimated using multivariable logistic regression and generalized estimating equations.

Results

Toxocara spp. seroprevalence was 80.7% in mothers and in children was 0%, 9.3%, 48.4%, 64.9%, and 80.9% at 7 months, 13 months, 2, 3 and 5 years, respectively. Risk factors significantly associated with increases in seroprevalence over the first 5 years of life in multivariable analyses were age [Odds ratio (OR) 2.06, 95% confidence interval (CI) 1.39–2.27, P < 0001], male sex (female vs. male: OR 0.66, 95% CI 0.48–0.89, P = 0.006), maternal ethnicity (non-Afro vs. Afro-Ecuadorian: OR 0.65, 95% CI 0.47–0.91, P = 0.011), lower maternal educational and socioeconomic level, and childhood STH (OR 2.29, 95% CI 1.51–3.47, P < 0.001). Seroconversion rates for infection were greatest at 2 years of age (3.8%/month). Factors associated significantly with seroconversion at 2, 3 or 5 years were childhood STH infection, male sex, and more frequent domestic cat exposure.

Conclusions

Our data, from an area of high Toxocara spp. endemicity, indicate no congenital transmission but high rates of seroconversion after 13 months of age reaching maternal levels of seroprevalence by 5 years of age. Factors associated with seroprevalence and seroconversion included STH infections, domestic cats, maternal ethnicity, male sex, STH infections, and markers of greater poverty.

Molecular and microscopic detection of natural and experimental infections of Toxocara vitulorum in bovine milk

Toxocara vitulorum is an Ascarid nematode infecting the small intestine of buffalo and cattle particularly neonate calves, with the postnatal route through milk is the main infection source. However, little is known about shedding rates and the optimum detection methods of T. vitulorum larvae in the milk of the infected bovine hosts. In this study, we aimed to evaluate the use of two methods, microscopy and PCR, and their detection limits both under the experimental and natural infection situations. In doing this, T. vitulorum eggs extracted from naturally occurring adult female worms were successfully subjected to experimental embryonation, and larvae were implemented in experimental infection of milk in ascending infection doses of 0, 1, 5, 10, 20, 50 larvae/2-ml milk samples. With the except of negative control, microscopy-based examination detected larvae in all samples, albeit with means, ranges, and the total number of larvae were detected in exponential rates relative to larvae densities in milk samples. PCR technique corresponded well to microscopy in detecting genomic DNA of T. vitulorum larvae in all milk samples down to a single larva/sample. On the other hand, and by applying the same methodology approach on 50 naturally-occurring bovine colostrum/milk samples, 13 (26%) and 20 (40%) samples were tested positive for T. vitulorum infection by microscopy and the PCR-based detection, respectively. Of these, 11 out of 26 buffalo samples (42.30%) and 2 out of 24 cow samples (8.33%) were tested positive by microscopy, while 16 (61.54%) and 3 (12.50%) of buffalo and cow samples were tested positive by PCR, respectively. By applying the Agreement Coefficient, substantial agreement (0.77) between molecular and microscopy detection was detected from all tested samples. In conclusion, larvae of T. vitulorum were unequivocally detected by microscopy and molecular methods in milk samples both under the experimental and natural field situations. Nevertheless, slightly higher rates by PCR than microscopy were obtained when detecting naturally-infected milk samples. To the best of our knowledge, this is the first in situ detection of larvae of T. vitulorum in the milk of the naturally infected animals.

High seroprevalence of Toxocara antibodies in pregnant women attending an antenatal clinic at a university hospital in Ile-Ife, Nigeria

BACKGROUND

Human toxocariasis is a neglected zoonotic disease and its impact on human health is underestimated. Studies investigating the occurrence of toxocariasis in pregnancy are very scarce in Nigeria. This study investigated the seroprevalence of Toxocara spp. antibodies as well as the possible risk factors in pregnant women who routinely attended an antenatal clinic in a university hospital in Ile-Ife, Osun state.

METHODS

Blood samples were collected from 413 participating pregnant women between October 2017 and February 2018. Epidemiological data were obtained through a structured questionnaire. The sera were screened for anti-Toxocara IgG antibodies by western blot technique based on Toxocara canis larval excretory-secretory antigens, targeting low molecular weight bands of 24-35 kDa, specifically for T. canis infection.

RESULTS

The overall seroprevalence was 92.49% (382/413). There was no significant difference in the seroprevalence rate of Toxocara spp. infection between pregnant women aged ≤30 y and those aged >30 y (91.63 vs 93.33%; OR 1.28, 95% CI 0.61 to 2.67, p=0.511). The seroprevalence rate increased with the number of miscarriages but there was no statistical significance (p>0.05). Moreover, no significant associations were found between Toxocara spp. seropositivity and other studied risk factors (p>0.05).

CONCLUSION

The high seroprevalence of Toxocara spp. in pregnant Nigerian women needs comprehensive health education regarding personal hygiene and how to avoid exposure to this parasite infection.

Seroprevalence of Toxoplasma gondii and Toxocara canis in a human rural population of Southern Rio Grande do Sul

Due to the growing population of pets, especially homeless dogs and cats, zoonoses still represent a significant public health problem. Toxoplasma gondii and Toxocara spp. are epidemiologically important zoonotic agents as they are etiological factors of human toxoplasmosis and toxocariasis, respectively. These parasites remain neglected even though they are substantially prevalent in rural areas. The aim of this study was to investigate T. gondii and T. canis seroprevalence and risk factors of seropositivity in a rural population in Pelotas municipality, Brazil. The study participants (n=344) were patients of a Basic Healthcare Unit (BHU) located in Cerrito Alegre. Blood samples were collected and tested for T. gondii antibodies by indirect immunofluorescence and T. canis antibodies by an indirect ELISA that targets an excreted-secreted antigen (TES). T. gondii seropositivity was 53.2%, with higher titers (1:256 - 1:1,024) in individuals who habitually eat pork, beef, or chicken, while T. canis seropositivity was 71.8% and concomitant T. gondii and T. canis seropositivity was 38.3%. Among the seropositivity risk factors assessed, only habitual undercooked meat consumption was significant (p = 0.046; OR = 3.7) for T. gondii and none of them were associated with T. canis seropositivity. Both parasites have a high prevalence in rural areas, which reinforces the need to invest in rural community education and health.

elevated trans-mammary transmission of Toxocara canis larvae in BALB/c mice

Toxocariasis is a widespread zoonosis and is considered an important worldwide public health problem. The aim of this study was to investigate the frequency of trans-mammary Toxocara canis infection in newborn BALB/c mice nursed by females experimentally infected with 1,200 eggs after delivery. After 50 days of age, the presence of larvae in different organs of the offspring was investigated. Trans-mammary infection was confirmed in 73.9% of the mice that had been nursed by infected females. These data show a high trans-mammary transmission of T. canis and confirm the significance of this transmission route in paratenic hosts.

Human toxocariasis: current advances in diagnostics, treatment, and interventions

Toxocariasis is a neglected zoonosis caused by the nematodes Toxocara canis and Toxocara cati. This disease is widespread in many countries, reaching high prevalence independently of the economic conditions. However, the true number of cases of toxocariasis is likely to be underestimated owing to the lack of adequate surveillance programs. Although some diagnostic tests are available, their sensitivity and specificity need to be improved. In addition, treatment options for toxocariasis are limited and are non-specific. Toxocariasis is listed as one of the five most important neglected diseases by the CDC. This review presents recent advances related to the control of toxocariasis, including new immunodiagnostics, therapies, and drug formulations, as well as novel interventions using DNA vaccines, immunomodulators, and probiotics.

Transmammary infection in BALB/c mice with chronic toxocariasis

Human toxocariasis is a neglected public health problem. Infection of humans generally results from the accidental ingestion of embryonated Toxocara canis eggs, but it is important to broaden knowledge about other forms of transmission. This study aimed to demonstrate the prevalence of transmammary transmission in mice with chronic toxocariasis. BALB/c mice in groups 1 (G1) and 3 (G3) were inoculated with 1200 T. canis eggs 60days before mating, whereas those of group 2 (G2) were not infected. After delivery, the G1 neonates were transferred to G2 females to be nursed, and vice versa. Thus, the mice generated by G2 females and breastfed by G1 females could be infected only during lactation. In the G3 group, offspring were not exchanged. The search for T. canis larvae in the bodies of the lactating females and their offspring was performed after weaning and at 60days old, respectively. The frequency of transmammary infection in the mice generated by G2 uninfected females and breastfed by G1 infected females was 19.8%, which was similar to that observed (19.6%) in the mice bred and fed by G3 females. The frequency of infection in the mice generated by G1 females and breastfed by G2 females was only 4.2%, which was lower than that of G1 (p=0.0064) and G3 (p=0.0062) groups. Transmammary infection by mice with chronic toxocariasis was found to be more prevalent than congenital infection.

The co-occurrence of Toxocaraocular and visceral larva migrans syndrome: a case series

Introduction

Ocular toxocarosis associated with high peripheral eosinophilia and together with systemic signs of visceral damage has been reported sporadically. Eye infections caused by numerous migrating larvae of Toxocara parasites, probably due to re-invasion or delayed reactivation, and leading to a progressive loss of vision is relatively rare. We report three atypical cases of toxocarosis with the co-existence of ocular larva migrans syndrome and generalized signs of Toxocara infection in schoolboys.

Case presentation

Two children aged 8 and 14 years respectively, with symptomatic ocular and visceral larva migrans syndromes, and one 16-year-old adolescent with chronic multifocal eye invasion, characterized by severe granulomatous retinochoroiditis with unilateral blindness, chronic abdominal pain and generalized synthesis of total immunoglobulin E antibody are described. The three patients, heavily infected with Toxocara species were boys of Polish origin. Ocular location of the parasite was confirmed by the detection of intraocular synthesis of specific anti-Toxocara immunoglobulin G antibody in aqueous humour samples from the affected eyes. Immunological parameters of tissue eosinophilia, allergy or hypersensitivity reactions to the presence of the migrating Toxocara parasites were analysed. Irreversible eye complications were observed in the patients with high level of exposure to Toxocara species in a contaminated environment, with a suggestion of possible re-activation or re-infection by different species or strains of the parasite.

Conclusions

Wide promotion of sanitary education is strongly justified in children and adolescents in Toxocara endemic areas in order to reduce the potential risk of primary invasion or re-infection with the parasites, which can lead to a severe course or progression of the disease. A long-term clinical follow-up and more intensive anti-parasitic treatment is recommended in patients with subclinical and overt forms of toxocarosis to prevent later reactivation of the migrating larvae in tissues.

The co-occurrence of Toxocara ocular and visceral larva migrans syndrome: a case series

INTRODUCTION

Ocular toxocarosis associated with high peripheral eosinophilia and together with systemic signs of visceral damage has been reported sporadically. Eye infections caused by numerous migrating larvae of Toxocara parasites, probably due to re-invasion or delayed reactivation, and leading to a progressive loss of vision is relatively rare. We report three atypical cases of toxocarosis with the co-existence of ocular larva migrans syndrome and generalized signs of Toxocara infection in schoolboys.

CASE PRESENTATION

Two children aged 8 and 14 years respectively, with symptomatic ocular and visceral larva migrans syndromes, and one 16-year-old adolescent with chronic multifocal eye invasion, characterized by severe granulomatous retinochoroiditis with unilateral blindness, chronic abdominal pain and generalized synthesis of total immunoglobulin E antibody are described. The three patients, heavily infected with Toxocara species were boys of Polish origin. Ocular location of the parasite was confirmed by the detection of intraocular synthesis of specific anti-Toxocara immunoglobulin G antibody in aqueous humour samples from the affected eyes. Immunological parameters of tissue eosinophilia, allergy or hypersensitivity reactions to the presence of the migrating Toxocara parasites were analysed. Irreversible eye complications were observed in the patients with high level of exposure to Toxocara species in a contaminated environment, with a suggestion of possible re-activation or re-infection by different species or strains of the parasite.

CONCLUSIONS

Wide promotion of sanitary education is strongly justified in children and adolescents in Toxocara endemic areas in order to reduce the potential risk of primary invasion or re-infection with the parasites, which can lead to a severe course or progression of the disease. A long-term clinical follow-up and more intensive anti-parasitic treatment is recommended in patients with subclinical and overt forms of toxocarosis to prevent later reactivation of the migrating larvae in tissues.