DOI: https://doi.org/10.21203/rs.3.rs-1815205/v1
Stray cats and dogs are the major risk factors for human toxocariasis and one of the most important public health issues. Accessing and analyzing the prevalence of Toxocara spp. in definitive host may help control and prevention of human toxocariasis. This systematic review and meta-analysis is the first study in Middle east, directed to estimate the prevalence of Toxocara cati, Toxocara canis and Toxocara leonina infection in cats and dogs by gender, age, geographical location, weather condition and other risk factors. Three English databanks (Scopus, PubMed, and Google Scholar) were searched for published articles about Toxocara parasites of cats and dogs in Middle-East from 1980 to 2022. Of 300 peer-reviewed articles, 40 were included in this review and represented cats and dogs from all over the Middle east countries. The collective prevalence (95% CI) of Toxocara cati infection in stray cats was 7.66%, being highest in north of Iran and lowest in Qatar countries. The collective prevalence (95% CI) of Toxocara canis infection in stray dogs was 26.34%, being highest in north of Iran and lowest in Israel countries. The collective prevalence (95% CI) of Toxocara leonina infection in stray cats and dogs was 2.85%, being highest in Egypt and lowest in Qatar countries. Prevalence of Toxocara leonina was higher in low-income tropical countries and also in young (12 months of age) cats and dogs and also higher in humid weather like north of Iran. Control prevention and of this zoonosis should take greater care by health officials particularly in countries where risk factors and prevalence are highest.
Surveying the incidence of Toxocara canis (T. canis) and Toxocara cati (T. cati) and Toxocara leonina (T. leonina) in canines and felines, separately, in the Middle-East could be a discouraging task, however basic to understanding the risk these parasites posture to environmental health management. Toxocariasis has been called a zoonotic disease for over fifty years and much data has gathered in regards to the study of disease transmission and pathogenesis of contaminations (Halsby et al., 2016; Hotez, 2020). T. canis transmitted by canines, and wild canids, especially foxes and is quite possibly the most inescapable general health (Chieffi et al., 2021). The significance of T. cati contamination to human Toxocariasis can't be unnoticed (Alho et al., 2021). Human toxocariasis (HT) is now considered as a major zoonosis with global and regional importance. The sort Toxocara (Ascaridoidea: Toxocaridae) includes upwards of 26 species, however just two are of significant public health concern, namely, T. canis and T. cati (Ziegler & Macpherson, 2019). Felines could be tainted with T. cati by the intake of embryonated eggs from paratenic hosts, soil or milk from the queen (Fakhri et al., 2018). Infective hatchlings, enter the gastrointestinal tube and afterward move through lungs to the aviation routes and liver (Holland, 2017). Next advance toward the small gut, wherein fourth-level larvae (L4s) inside 2–3 months alternate to the grown-up stage (Chen et al., 2018). A feminine worm will produce as much as 200,000 eggs each day (Tyungu et al., 2020). Eggs being shed in conclusive hosts stool and turn out to be embryonated withinside the surroundings inside 2–3 weeks on the off chance that the moistness and temperature are proper (Hajipour, 2019). Eggs are lenient, living unlarvated for a long time even in state change things, and as soon as larvated ultimate possible for no less than about a month (Carlin & Tyungu, 2020). If T. canis eggs ingested by canids, the eggs will hatch and therefore the larvae will relocate via the liver to the lungs wherever an extent will leave the circulation system (Wu & Bowman, 2020). Next return to the small digestive tract where they have been mature (Schwartz et al., 2022). Others continue to be withinside the blood to be dispensed in the course of the tissues of the frame as resting 2d level larvae as much as 0.45 mm long (Papavasilopoulos et al., 2018). The quantity of larvae taking every of the one-of-a-kind pathways relies upon at the age and intercourse of the host. In puppies practically all can continue to the digestive tract, while the incredible heft of hatchlings in rearing bitches will by skip into the substantial tissues (da Silva et al., 2018). The following significant period of the lifestyles cycle of T. canis takes place whilst a bitch holding onto stationary larvae turns into pregnant (Ketzis & Lucio-Forster, 2020). After approximately the forty-tow day of incubation, an extent of the hatchlings become dynamic and pass the placenta to develop within the embryo (Araújo et al., 2018). An excess populace of hatchlings deposits in the somatic tissues and might turn out to be initiated at some stage in a resulting pregnancy (Awadallah & Salem, 2015). Larvae within the mammary organ is also passed to the suckling puppy through the milk (Telmo et al., 2015). In humans, a new classification of clinical toxocariasis was proposed which included: classic and incomplete (VLM) visceral larva migrans syndrome (Rostami et al., 2019), ocular toxocariasis (OLM) (Badri et al., 2021), neurological toxocariasis (NLM) (Fan et al., 2015; Ma et al., 2018; Meliou et al., 2020) and covert toxocariasis) CT) (Zibaei et al., 2019). Regardless of the clinical acknowledgment of these disorders and the rising cognizance that human Toxocariasis is making a rising weight general wellbeing, noticeably in subtropical and tropical areas and in impeded communities in certain nations, there are as yet significant holes in the comprehension of this infection. Considering the general public health problems with reference to cats and dogs as a source of Toxocara infection, an outline of knowledge on the Middle-East prevalence of Toxocara infection in cats and dogs is very important for veterinarians, medical practitioners and public health officers the same.
Three English databanks (Scopus, PubMed, and Google Scholar) were searched for published articles about Toxocara parasites of cats and dogs in Middle-East from 1990 to 2022. The language of data collection was limited to English and Persian and Arabic. The keywords used alone or in combination were: “Toxocara canis,” “Toxocara cati,” “Toxocara leonina,” “dogs,” “cats,” “prevalence,” and “Middle-East.” All Iranian veterinary and parasitology journals were wisely analyzed. All references from each article were systematically checked, to evade missing any records.
Extracted data from the records included information about the first author, sample size, number of positive samples, province of the study, year of publication, diagnostic method.
All the data on prevalence, countries, sample number, were analyzed by ANOVA coupled with post hoc tests (SPSS ® Software version 16). The discrepancy was considered statistically significant at the P-value < 0.05 for all the analyzed data.
3.1. Middle-East and regional prevalence of Toxocara cati and analyzing all the risk factors:
The collective prevalence of Toxocara cati infection in stray cats was 7.66%(95% CI, 6.79-8.58%; Table 1), being highest in north of Iran and lowest in Qatar countries.
3.2. Middle-East and regional prevalence of Toxocara canis and analyzing all the risk factors:
The collective prevalence of Toxocara canis infection in stray dogs was 26.34% (95% CI, 24.13-28.60%; Table 2), being highest in north of Iran and lowest in Israel countries.
3.3. Middle-East and regional prevalence of Toxocara leonina and analyzing all the risk factors:
The collective prevalence of Toxocara leonina infection in stray cats and dogs was 2.85% (95% CI, 2.26-3.49%; Table 3), being highest in Egypt and lowest in Qatar countries.
Toxocariasis is a parasitic zoonosis with international distribution that influences each cats and dogs: Toxocara canis, Toxocara cati and Toxocara leonina. Considerate the parasite epidemiological pattern is very important for discount of the chance to people. Dogs play a critical role in continuing the cycle of transmission of many parasitic zoonoses (Waindok et al., 2021). The effect of these diseases can be deadly, as in the case of T. canis, (HT) occurs by inadvertent ingestion of infectious larvae (Abbaszadeh Afshar et al., 2020). Close contact between people and pets can be responsible for the extreme endemicity of those zoonotic sicknesses (Raissi et al., 2018). Human infection happens with using inadvertent ingestion of eggs, and, to a lesser extent, via pica and consuming the paratenic hosts, including cattle, lamb, pig, chicken and earth worms (Farmer et al., 2017; Luna et al., 2018). Humans also can have infected with T. canis through direct conversation with puppies (Otero et al., 2018), despite the fact that occurrence of T. canis in stray dogs can be meaningfully extra than domestic dogs, the primary hazard for human exposure are home puppies which regularly interplay their owners (Fialho & Corrêa, 2016). Also, examining canine hair can also release an extreme range of eggs and human hands can be infected via the touching and comb the canine’s hair (Berrett et al., 2017). Additionally, through self-cleaning T. canis eggs could be spread from the anal area to distinct parts of body in which humans may be more likely to touch (Maurelli et al., 2019). The current scholarship suggests a stepped forward threat of T. canis infection in puppies in contrast with adult dogs, and brought into attention puppies are a crucial danger aspect for human infection. Young dogs are being able to be infested from their mother through transmammary transmission and transplacental (Ma et al., 2019). As displayed in our work, age issue become negatively linked to functionality contamination which incomes that more youthful puppies are at extra critical hazard of infection that might be attributed to a lot much less superior immune system. Furthermore, the expected immoderate prevalence of T. canis recorded withinside the puppies with age 0–6 months. To our information, a success improvement of helminth eggs relies upon on suitable weather conditions. Though, that would clarify the higher transmission rate detected in our neighborhood at summer time (Kleine et al., 2017). Likewise, it would recommend that Toxocara spp. has the perfect situations for improvement and hatch in summer and fall, while excessive temperatures (25–30°C), humidity close to 80% (Abou-El-Naga, 2018).Infection of cats with T. cati can happen both via ingestion of infective eggs or from feeding on rodents containing larvae in their tissues (Lucio-Forster et al., 2016). Toxocara eggs are proof against low temperatures and excessive humidities however desiccation and direct daylight will lower infectivity.
The outcomes of the current study advise that kittens are more possible to harbor eggs on their hair than grownup cats (Nijsse et al., 2016). Age was initiate to be a serious risk factor related to parasitic contamination. It is likely that contamination can happen at any age, both via tissues containing the larvae or ingestion of embryonated eggs, despite the fact that the best prevalence of contamination happens in kittens (Eslahi et al., 2020). It has been recommended that the EPG of Toxocara is higher in the hair of infected animals than in the soil. Therefore, eating T. cati eggs through direct cat interaction may be less difficult than from the ground, as evidenced by the records in this article. Also, the presence of embryonated eggs in a number of those hair samples includes direct interaction with those cats and can be higher risk than soil infection for the transmission of human toxocariasis. In our evaluation, Toxocara incidence reduced with rising latitude. This end result is according with discoveries of different latest meta-analyses, which validated a related trend in dogs and people in addition to the environmental infection of public locations. It may be advised that this lowering trend in incidence of contamination with growing geographical range can be because of advanced, and veterinary take care of pets. Stray animal prevention and environmental sanitation practices are also comparatively common, regular and accessible. In such countries, people may be more aware of zoonoses and closer to a healthcare facility. In contract with Ali Rostami 2020, our results in the current and former article have displayed that the incidence rates of Toxocara contamination in cats, dogs are pointedly lower in countries with excessive mean earnings levels compared with those low incomes (Rostami et al., 2020). One greater clarification is probably that higher latitudes has low environmental temperatures that impact the rate of embryonation and the survival of Toxocara eggs. Situations that favor the embryonation and existence of Toxocara eggs are dark, appropriate environmental temperature (15–30°C), excessive mean comparative humidity (> 60%) and excessive oxygen content in soil (Ghomashlooyan et al., 2015).
Funding:
No funding was received for conducting this study.
Conflict of interests:
The authors declare no conflict of interest.
Data availability:
The datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request.
Author contribution:
Conceptualization: [Hassan Borji], …; Methodology: [Ehsanallah Afshari Safavi], …; Formal analysis and investigation: [Amir Hossein Atazadeh, Mohammad Javad Haratizadeh], …; Writing - original draft preparation: [Soheil Sadr, Safa Moghadam]; Writing - review and editing: [Soheil Sadr, Safa Moghadam], …; Funding acquisition: [No funding], …; Supervision: [Hassan Borji]
Compliance with Ethical Standards:
Ethical approval: All applicable international, national, and/or institutional guidelines for the care and use of animals were followed.
Consent to participate:
Not applicable
Consent for publication:
Not applicable
Acknowledgments:
We would like to thank research deputy of Ferdowsi University of Mashhad for support.
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