Psychiatric Clients with Toxocara- A Critical Review and Research gap analysis

 

Dr. Sampoornam. W

Associate Professor, Mental Health Nursing Department, Dhanvantri College of Nursing Pallakkapalayam, Namakkal. Tamilnadu, India

 

ABSTRACT:

Toxocariasis is asymptomatic as the larvae are unable to reproduce and subsequently die, but local inflammation can lead to distinct syndromes depending on where in the body the larvae reside. In rare cases these larvae may migrate to the central nervous system where they may cause a constellation of neurological symptoms including meningoencephalitis, focal deficits and seizures. The reports of toxocariasis shows causative factor of psychiatric symptoms. Several studies have highlighted the increased seroprevalence of antitoxocara antibodies in psychiatric populations particularly schizophrenia, although it is uncertain whether is a causative effect or secondary to the population’s increased likelihood to behave strangely or be homeless. Recently, there has been interest in the possible association between neurotoxocariasis and an immune-mediated dementia.

 

 

INTRODUCTION:

Toxocariasis is a zoonotic condition. Zoonotic conditions spread from animals to humans. Mentally ill patients are highly susceptible for toxocara due behavioral disturbances. Among the Nematodes belonging to the genus Toxocara, only 2 species, Toxocara canis and T. cati, are recognized as causative agents of human toxocaral disease (Fisher M, 2003). The genus of helminths, toxocara, is universal among domestic dogs, cats and wild animals such as foxes. Humans can become accidental hosts when they ingest toxocara larvae often from soil contaminated with faeces or from unwashed vegetables or undercooked meat. Toxocariasis is not diagnosed promptly due to non specific symptoms and ignorant epidemiological statistics (Macpherson CN, 2013).

 

It is more common in schizophrenic patients which are predominantly seen in rural settings (Kaplan M, Kalkan A, Kuk S, et al, 2008). Psychiatric patients have a higher seroprevalence of toxocariasis than general population. However, there is poor knowledge about any specific psychiatric diagnosis associated with toxocariasis.

 

Epidemiological statistics:

Toxocariasis is a significant problem in developing countries and low income neighborhoods. In India, several surveys on toxocariasis revealed prevalence in dogs ranging from 4.95 to the exact geographical location 38.13 % (Traub et al. 2002; Subhash and Tanwar 2007; Khante et al. 2009). In India prevalence studies on human toxocariasis shows that the children who have the habit of eating raw vegetables were more prone to infection (36.48 %) than those who were not (20.31 %) and children with the habit of geophagia were more vulnerable to this infection (36.48 %) (Ahmad et al. 2002). Dar et al. (2008) evaluated that water pretreatment was a significant risk factor for the prevalence of toxocariasis infection.

Clinical Manifestations:

Toxocara infection exhibits various syndromes in humans, which can be classified as either generalized forms, including major and minor syndromes or compartmentalized forms.

 

Generalized forms:

Major syndrome:

This syndrome is caused by ingesting large amounts of embryonated eggs of Toxocara and is generally reported in children living in poor socioeconomic status and individuals suffering from mental retardation or severe psychiatric disorders with pica or geophagia. The clinical picture comprises an impairment of the general status that includes weight loss and fever along with asthmatic cough, wheezing, generalized lymphadenopathy, hepatomegaly and often Loffler’s infiltrates in chest X-ray (Ehrard T, Kernbaum S, 1979).

 

Minor syndrome:

Syndrome includes chronic weakness, digestive pain, various allergic signs often conjunctival or cutaneous such as itchy rash or pruritus, diffuse myalgias, an irritating cough and in children sleeping and behavior disturbances. This clinical form was termed “covert toxocariasis" (Glickman LT, Magnaval JF, 1987).

 

Compartmentalized forms:

The disease includes ocular and neurological toxocariasis.

 

Ocular Toxocariasis:

Chronic inflammation of the eye wall, anterior uveitis or more often posterior uveitis, hyalitis, chorioretinitis, opacification of the vitreous humor and further development of fibrous traction bands that result in retinal detachment, retinal granuloma and vision loss (Ahn SJ, Woo SJ, 2014).

 

Neurological Toxocariasis:

Meningitis, Meningoencephalitis or Transverse Myelitis and Epilepsy (Fellrath JM, Magnaval JF, 2014).

 

In vitro Bio-physiological parameter:

The most commonly performed serological diagnostic test is an Enzyme-Linked Immunosorbent Assay (ELISA) employing excretory, secretory antigens from T. canis larvae (De Savigny DH, Voller A, 1979). The diagnosis of toxocariasis was exactly made after western blot and ELISA returned positive results for high titres of toxocara IgM antibodies. Blood test highlights eosinophil count, stool culture and serological screen for parasites.

 

 

 

Prophylaxis:

Albendazole is the tentative drug of choice although the evidence is marginal. Two benzimidazole (Thiabendazole, Mebendazole) agents are available or efficient (Magnaval JF, Charlet JP, 1987). Diethylcarbamazine is an alternative agent. Remarkable improvement is seen in cognitive function (Dementia client) after treatment with albendazole (Lawton S, Sharma A, 2017).

 

Prevention:

There are several ways to prevent toxocara infection in both dogs and humans. Regular de-worming by veterinarian is important to stop re infection. Good practices to prevent human infections include washing hands before eating and after disposing of animal feces in a timely manner. Teach children not to eat soil and cook meat to a safe temperature in order to kill potentially infectious eggs.

 

Research Gap Analysis:

A study conducted in Turkey, toxocara seroprevalence was much higher in schizophrenic patients (45.9%) than in the general population (2%). Another research work examined eosinophilia in peripheral blood detection 61.9% of seropositive schizophrenic patients which significantly differed to the mentally healthy population (El-Sayed NM, Ismail KA, 2012).

 

There is mounting evidence linking toxocara that leads to changes in mood or personality even though the infectious agent is widely believed to be harmless in more than 80% of infected people. Numerous studies published in recent years have suggested that toxoplasma infection increases the chances of developing serious psychological disturbances such as schizophrenia and bipolar affective disorder. Scientists have shown that toxoplasma is linked with more subtle psychological changes such as increased reaction times. Institutionalized mentally challenged patients increase the risk of toxocariasis (Mustafa Kaplan, Ahmet Kalkan etal, 2004). Many people who are infected with toxocara remain asymptomatic, only children do develop symptoms which include cough, abdominal pain, headaches and behavioral or psychiatric problems. There is much evidence to suggest that schizophrenia disorder is associated with toxoplasmosis. The schizophrenic state seems to present a high risk for Toxocara infection in Turkey, (Kaplan M, Kalkan A, Kuk S, et al, 2008).

 

Due to poor hygiene, the prevalence of Toxocara is higher in most localities of Iran than any elsewhere in the world. With prevalence rate of approximately 50% in Iran, toxoplasmosis continues to be a public health problem (M. Assmar, A. Amirkhani, 1997). Association between Toxoplasma gondii and schizophrenia has paid little attention in Iran. Considering the correlation between lifestyle and Toxocara infection, which is commonly seen in areas with abnormal behaviors and poor personal hygiene observed in patients with schizophrenia. Research study suggests that patients with schizophrenia disorder are at an elevated risk for Toxocara spp. Infection (Shahram Khademvatan 2014).

 

The literature about toxocariasis epidemiology in psychiatric patients is very sparse. Toxocara seroprevalence (45.9%) was much higher in schizophrenic patients than in the general population. These results suggest that the schizophrenic state presents a high risk for Toxocara infection. Seroprevalence of Toxocara exposure was low and not associated with schizophrenia in psychiatric inpatients in Durango City, Mexico. T. canis seropositivity in schizophrenic patients (23.3%) is significantly higher than the control group (2.2%) (Nagwa Mostafa, 2012). Moreover, Huminer et al identified Toxocara infection with 8.5% among institutionalized mentally challenged adults in Israel. The presence of Toxocara spp. larvae in the central nervous system may cause some neurological and psychiatric disorders including schizophrenia. Increased dopamine activity in hippocampus and influenced impaired learning processes and memory are the main mechanisms of the neuropsychiatric complications. The relationship between schizophrenia and increased toxoplasma antibodies level was found as far as the OCD symptoms. Neuropsychiatric manifestations are rarely specific. The most clinically important are epilepsy, dementia, cognitive and affective impairment.

 

The conflicting results on association of Toxocara seropositivity and schizophrenia might be explained by differences in the characteristics of the study populations. However, it is not clear whether any specific psychiatric diagnosis is associated with toxocariasis. Further studies to elucidate the association of toxocariasis with schizophrenia are needed (Cosme Alvarado-Esquivel, 2014). There might be a causal relationship between toxocariasis and schizophrenia, either Toxocara may be a possible etiologic agent of schizophrenia or the schizophrenic patients constitute a high risk for Toxocara infection. Further studies will be needed to realize the actual relationship between them, (Nagwa Mostafa, 2012).

 

CONCLUSION:

Toxocariasis is under-diagnosed due to non-specific symptoms and poor awareness of its epidemiology and is more common in schizophrenic patients and those that have spent a lot of time in rural settings. It is therefore the responsibility of the psychiatrist and the nurse consultant to consider it as part of a differential diagnosis.

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Received on 01.06.2017           Modified on 20.06.2017

Accepted on 28.07.2017         © A&V Publications all right reserved