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 ~ Introduction
 ~  Materials and Me...
 ~ Results
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  Table of Contents  
Year : 2018  |  Volume : 36  |  Issue : 3  |  Page : 432-434

Clinical and laboratory characteristics of patients with toxocariasis encountered at a tertiary care centre in North India

1 Department of Medical Parasitology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
2 Department of Pediatrics, Postgraduate Institute of Medical Education and Research, Chandigarh, India

Date of Web Publication14-Nov-2018

Correspondence Address:
Dr. Sumeeta Khurana
Department of Medical Parasitology, Postgraduate Institute of Medical Education and Research, Chandigarh - 160 012
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijmm.IJMM_18_259

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 ~ Abstract 

Toxocariasis is a neglected soil-transmitted helminthic infection caused by either Toxocara canis or Toxocara cati where humans get infected by accidental ingestion of embryonated eggs, and the definitive hosts are dogs and cats. This study aims to analyse the clinical and laboratory characteristics of Toxocara-infected patients and assessment of response to standard treatment with review of literature. The clinical details of patients with Toxocara serology positive for IgG antibodies by ELISA in 5 years (2013–2017) were retrospectively analysed. A total of 29 patients with clinical features and serology suggestive of Toxocara infection were evaluated. A complete history of 14 patients was available for the analysis. Majority (13/14; 96.5%) of cases were children <15 years, males (79%) and belonged to lower socioeconomic status (64.3%). The most common clinical presentation was fever (78.5%) with respiratory symptoms (57%) followed by gastrointestinal features (35.7%). All the patients had eosinophilia (range 8.3%–85%) and raised total IgE levels. Toxocariasis is more common in children, and the true prevalence may be underestimated. In endemic areas, Toxocara workup should be considered in patients with eosinophilia presenting with respiratory and gastrointestinal features.

Keywords: Eosinophilia, ocular, serology, Toxocara, visceral larva migrans

How to cite this article:
Ain Tiewsoh JB, Khurana S, Mewara A, Sehgal R, Singh A. Clinical and laboratory characteristics of patients with toxocariasis encountered at a tertiary care centre in North India. Indian J Med Microbiol 2018;36:432-4

How to cite this URL:
Ain Tiewsoh JB, Khurana S, Mewara A, Sehgal R, Singh A. Clinical and laboratory characteristics of patients with toxocariasis encountered at a tertiary care centre in North India. Indian J Med Microbiol [serial online] 2018 [cited 2020 Jul 7];36:432-4. Available from:

 ~ Introduction Top

Toxocariasis is a soil-transmitted helminthic infection caused by either Toxocara canis or Toxocara cati where the definitive hosts are dogs and cats. Humans may acquire toxocariasis either by ingestion of infective eggs from contaminated fruits or vegetables, soil or water or playing with dogs or cats or by ingestion of larvae in raw or undercooked meat or organs from paratenic hosts, such as cattle, sheep and chickens. Except in the definitive host, the 3rd stage larvae do not mature but remain developmentally arrested in tissues for many years evoking an inflammatory immune response. Although most human infections are subclinical, it can manifest as syndromes, namely (i) visceral larva migrans (VLM), (ii) ocular larva migrans (OLM), (iii) neurotoxocariasis and (iv) covert or common toxocariasis. VLM is the most common syndrome especially in children, with clinical features of respiratory system involvement or cutaneous manifestations. OLM too is mostly reported in children and presents as chronic endophthalmitis, retinitis or granulomata involving mainly one eye. Neurotoxocariasis involving nervous system is rare. Covert toxocariasis in children and common toxocariasis in adults are difficult to diagnose clinically because of non-specific symptoms. The disease is usually associated with moderate-to-high levels of anti-Toxocara serum antibody titres and eosinophilia.[1],[2],[3],[4] Here, we retrospectively analysed the sociodemographic pattern, clinical presentation, laboratory profile and treatment response in Toxocara-infected patients in North India.

 ~ Materials and Methods Top

For this retrospective laboratory-based analysis, patients with Toxocara infection diagnosed on the basis of positive anti-Toxocara IgG antibodies between 1st January 2013, and 31st December 2017, were included in this study. The qualitative determination of antibodies against T. canis specific IgG was carried out using ELISA kit (NOVALISA™ T. canis IgG, NOVATEC Immundiagnostica GmbH, Germany). The socio-demographic details including the age, sex, month of admission, economic status, occupation, education of adult patients and parents in case of children were obtained on a predesigned pro forma. The exposure history such as dog and cat contact, dietary habits, geophagia/pica, deworming and faeces/waste disposal, chief presenting complaints, laboratory investigations including complete blood haemogram, erythrocyte sedimentation rate (ESR), total IgE, stool examination and serological tests for parasitic co-infections and treatment were obtained.

 ~ Results Top

A total of 203 patients were tested for anti-T. canis-specific IgG antibodies, of which 29 (14.28%) were positive. Majority were children (96.5%; 28/29) with mean age of 6.8 years (range 3–11 years) and were males (79%; 23/29). Most patients were treated as outpatients (69%; 20/29). A seasonal variation was noted with majority of the patients presenting during and after post-monsoon season (June to September 58.6%; 17/29). The complete clinical history was available for 14 patients, the majority of which were of lower socio-economic status (64.3%; 9/14); parents being manual labourers (57%; 8/14) who had education below 12 standard. Most patients were vegetarian (71.4%; 10/14) and from rural background (71.4%; 10/14). An ownership of cats and dogs was there in 28.5% (4/14) patients. Routine school-based mass deworming was received by 71.4% (10/14) patients, and all the patients had personal toilets.

A majority of patients presented with fever (78.5%; 11/14) followed by respiratory symptoms such as cough, shortness of breath, bronchitis and chest pain (57%; 8/14). Gastrointestinal features such as pain abdomen, nausea, vomiting, dysgeusia were present in 35.7% (5/14) patients. Hepatomegaly was present in 28.5% (4/14) patients; and lymphadenopathy and rashes in one patient each. Pica/geophagy was observed in 35.7% (5/14) patients. None of the patients presented with ocular manifestations. The stool microscopic examination for other parasitic coinfection was negative in all. Four of the patients, however, were found positive for IgG anti-Echinococcus granulosus antibodies while two were positive for anti-Toxoplasma IgM antibodies and 1 for anti-Wuchereria bancrofti IgG antibodies also. All the blood investigations of all patients showed eosinophilia >5% (range 8%–85%) and a raised total IgE with a range of 134 to >10,000 kU/L. Anaemia was documented in 50% (7/14) but most had mild anaemia (10–11.5 g/dL) and only two patients had moderate anaemia (7–<10 g/dL). A raised total leucocyte count was observed in 50%, neutropenia in 64.3% and raised ESR in 75% of the patients.

The majority of the patients were treated with albendazole 400 mg BD (85.7%; 12/14) or mebendazole 200 mg BD (7.1%; 1/14) for 5 days. Diethylcarbamazine at a dose of 25 mg TID x 14 days alone was administered in one patient while two patients received DEC along with albendazole. Steroids (prednisolone 2 mg/kg body weight/day) were also prescribed in nearly one-third of patients for 2–3 weeks (35.7%; 5/14). All the patients except one responded favourably to the treatment. However, the eosinophil counts gradually decreased by about 20% in first 2–3 weeks of therapy. The blood counts of two patients were available after >8 weeks, and it was observed that the eosinophil counts reverted to normal value while one patient continued to have hypereosinophilia and raised total IgE even after more than 3½ months of follow-up.

 ~ Discussion Top

Toxocara infection is a zoonosis with a worldwide distribution.[1],[2] In our analysis, the most commonly affected age group was that of children of the male gender which is similar to other studies.[1],[2],[3],[4],[5],[6] Similarly, the majority of patients were from lower socioeconomic strata as in other studies.[4],[7] Majority of cases presented during monsoon and post-monsoon season which may be due to higher chances of contaminated water or food. A majority of the patients in our study were vegetarians which may have acquired the parasite by ingestion of contaminated raw vegetables and fruits.[1],[3] However, infection in nonvegetarians may be due to ingestion of raw or undercooked meat.[1],[3] Having pets in the household and eating habits of children like pica/geophagia have been proven to be risk factors, and 28% patients in our study owned pets while 43% had pica.[1],[2],[3],[4],[6],[7] All the patients were found negative for intestinal parasites. This may be due to the school-based deworming programmes of the Government. However, single dose of albendazole is not effective for treating Toxocara infection. A majority of the patients presented with fever followed by pulmonary and gastrointestinal symptoms as described in other studies also.[1],[3],[6] While none presented with ocular toxocariasis which otherwise is a common manifestation of toxocariasis especially in children.[8]

In our study, anti-E. granulosus antibodies were detected in 28.5% (4/14) patients. Cross-reactions with other helminths in serological tests are documented by other authors too which may be confirmed or refuted by further western blotting test.[9] Toxoplasma co-infection has also been documented by other workers which may be due to the common mode of infection and same definitive host.[10] The complete blood picture showed eosinophilia and raised total IgE in all patients with toxocariasis is in concordance with other studies and prompts the clinicians to investigate parasitic aetiology.[1],[2],[3],[6],[8],[11] We also found anaemia, leucocytosis, neutropenia and raised ESR in the majority of the patients which is described in other studies also.[7],[12] Elefant et al. also concluded that the leucocyte, eosinophil and IgE present a significant decrease in the 1st year of treatment and that the latter two parameters be used for follow-up after chemotherapy. However, leucocytosis is not a favourable diagnostic marker for toxocariasis.[13]

A majority of the patients were treated by albendazole which is preferred to mebendazole and diethylcarbamazine. Steroids were added in few cases to relieve symptoms caused by allergic responses.[1],[3],[6],[8],[13] Most of our patients responded clinically to the therapy, but the eosinophil count was slow to revert to normal values. However, most of our patients could not be followed up long enough for blood values to return to normal. Kim et al. described cure and improvement of eosinophilia with albendazole alone or in combination with steroids in more than 80% of the patients, but it took 1 week–4 months.[14] However, Hombu et al. showed that albendazole had 78% recovery rate when used for 4 or 8 weeks, which was much higher than the 5 days' regimen.[15]

 ~ Conclusion Top

Toxocariasis is more common in children, and the true prevalence may be underestimated. A raised eosinophil count, ESR and IgE levels in a paediatric patient, should raise a suspicion of parasitic aetiology. Furthermore, efforts to increase the awareness of toxocariasis in treating physicians and the community are essential to implement preventive steps for this disease.

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Conflicts of interest

There are no conflicts of interest.

 ~ References Top

Ma G, Holland CV, Wang T, Hofmann A, Fan CK, Maizels RM, et al. Human toxocariasis. Lancet Infect Dis 2018;18:e14-24.  Back to cited text no. 1
Cassenote AJ, Lima AR, Pinto Neto JM, Rubinsky-Elefant G. Seroprevalence and modifiable risk factors for Toxocara spp. In Brazilian schoolchildren. PLoS Negl Trop Dis 2014;8:e2830.  Back to cited text no. 2
Woodhall DM, Fiore AE. Toxocariasis: A review for pediatricians. J Pediatric Infect Dis Soc 2014;3:154-9.  Back to cited text no. 3
Lee RM, Moore LB, Bottazzi ME, Hotez PJ. Toxocariasis in North America: A systematic review. PLoS Negl Trop Dis 2014;8:e3116.  Back to cited text no. 4
Mirdha BR, Khokar SK. Ocular toxocariasis in a North Indian population. J Trop Pediatr 2002;48:328-30.  Back to cited text no. 5
Despommier D. Toxocariasis: Clinical aspects, epidemiology, medical ecology, and molecular aspects. Clin Microbiol Rev 2003;16:265-72.  Back to cited text no. 6
Rubinsky-Elefant G, Hirata CE, Yamamoto JH, Ferreira MU. Human toxocariasis: Diagnosis, worldwide seroprevalences and clinical expression of the systemic and ocular forms. Ann Trop Med Parasitol 2010;104:3-23.  Back to cited text no. 7
Van Den Broucke S, Kanobana K, Polman K, Soentjens P, Vekemans M, Theunissen C, et al. Toxocariasis diagnosed in international travelers at the institute of tropical medicine, Antwerp, Belgium, from 2000 to 2013. PLoS Negl Trop Dis 2015;9:e0003559.  Back to cited text no. 8
Poeppl W, Herkner H, Tobudic S, Faas A, Mooseder G, Burgmann H, et al. Exposure to Echinococcus multilocularis, Toxocara canis, and Toxocara cati in Austria: A nationwide cross-sectional seroprevalence study. Vector Borne Zoonotic Dis 2013;13:798-803.  Back to cited text no. 9
Jones JL, Kruszon-Moran D, Won K, Wilson M, Schantz PM. Toxoplasma gondii and Toxocara spp. Co-infection. Am J Trop Med Hyg 2008;78:35-9.  Back to cited text no. 10
Akuthota P, Weller PF. Eosinophilic pneumonias. Clin Microbiol Rev 2012;25:649-60.  Back to cited text no. 11
Fialho PM, Corrêa CR. A systematic review of toxocariasis: A neglected but high-prevalence disease in Brazil. Am J Trop Med Hyg 2016;94:1193-9.  Back to cited text no. 12
Elefant GR, Shimizu SH, Sanchez MC, Jacob CM, Ferreira AW. A serological follow-up of toxocariasis patients after chemotherapy based on the detection of IgG, IgA, and IgE antibodies by enzyme-linked immunosorbent assay. J Clin Lab Anal 2006;20:164-72.  Back to cited text no. 13
Kim HB, Seo JW, Lee JH, Choi BS, Park SG. Evaluation of the prevalence and clinical impact of toxocariasis in patients with eosinophilia of unknown origin. Korean J Intern Med 2017;32:523-9.  Back to cited text no. 14
Hombu A, Yoshida A, Kikuchi T, Nagayasu E, Kuroki M, Maruyama H, et al. Treatment of larva Migrans syndrome with long-term administration of albendazole. J Microbiol Immunol Infect 2017. pii: S1684-1182(17) 30142-1.  Back to cited text no. 15


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