A mini Review of New Potential Therapeutic Strategies Against Trichinellosis

Trichinella spiralis is a parasitic nematode transmitted through the consumption of contaminated meat. The study aims to provide comprehensive information on various aspects of


INTRODUCTION
Trichinellosis is a parasitic disease with diverse manifestations, ranging from gastrointestinal symptoms to severe muscle pain and potentially life-threatening complications.Conventional treatment involves anthelmintic medications and supportive care, while new anti-trichinellosis strategies aim to improve treatment outcomes and address emerging challenges associated with the disease.

Trichinella:
This statement means that nematodes, which are a type of worm-like parasite, are found in many different places and environments, and they have adapted to live in various ways.These adaptations allow nematodes to occupy different niches or roles within ecosystems, such as living as parasites in animals or plants, or even as free-living organisms in soil or water.Their widespread distribution and ability to adapt to different lifestyles make nematodes significant members of many ecosystems (Tahir Aleem et al., 2022).Trichinellosis is a zoonotic disease that is initiated by roundworms of the genus Trichinella spp.(Abou Rayia, et al., 2022) and worldwide distributed in almost 30% of countries with a record of about 10000 cases/year (Pozio, 2007;Rawla and Sharma, 2022).Trichinella is the smallest nematode parasitizing humans with a clinically significant impact (Pozio, 2015).The disease has a substantial public health impact on humans as well as high economic cost in terms of pig husbandry and food safety (Nöckler et al., 2005) as it results in high rates of morbidity and mortality (Al-Attar et al., 2020;Bai et al., 2022).
Over 8000 Trichinella isolates from all over were identified by the International Trichinella Reference Centre (ITRC) (Marucci et al., 2022).Seven species of Trichinella infesting humans are documented.Three of them have a significant clinical impact on humans as they all have encysted larvae in the muscles; Trichinella spiralis is cosmopolitan, and Trichinella nativa is found in the Arctic, and sub-Arctic region, However, Trichinella britovi is found in Eurasia, and Africa (Gómez-Morales et al., 2018).The species, T. spiralis, pigeonholed one of the top ten foodborne parasites worldwide (El Temsahy et al., 2015).T. spiralis can infect more than 100 different species of animals, including mammals, birds, and reptiles (Gottstein et al., 2009;Bai et al., 2022).Pigs are the main definitive hosts in T. spiralis' life cycle (Basso et al., 2022).Only in China, more than 400,000 people are in perilous of trichinellosis, as China is one of the highest countries in breeding and consuming pig meats (Chávez-Ruvalcaba et al., 2021).By consuming raw or undercooked meat infested with T. spiralis larvae, humans get infected.The US Food and Drug Administration (USDA) endorses raising the internal heat of the meat during cooking to 76.7 °C to be enough to kill the larvae (Bacon and Sofos, 2003).

Manifestation of Trichinellosis:
Trichinella typically possesses two phases within their hosts; the intestinal (enteric) phase for 1-2 weeks and the muscular (parenteral) invasive phase (Darwish et al., 2022).The manifestation of Trichinella initiates in the intestine with several gastric symptoms including colic, diarrhea, seasickness, and queasiness (Rawla and Sharma, 2022).In the parenteral phase, Trichinella larvae enter striated muscle cells and encyst within it lasting viable for 1 year to several years reliant on Trichinella species (Bruschi et al., 2002).At the parenteral phase, malaise, fever, marked eosinophilia, and widespread myalgias for up to 8 weeks are common (Sethi et al., 2010).Myalgia is particularly in the rib cage, mid-abdomen, and face caused by released larvae (Bai et al., 2022;Rawla and Sharma, 2022).
The clinical representation of Trichinella infection fluctuates from asymptomatic to fatal depending on the number of larvae and site of invasion within the host body (Rosca et al., 2021).Generally, the clinical picture of trichinellosis includes fever, inflammation of muscles, fatigue, gastrointestinal symptoms, occasional bleeding in the retina, and decreasing in cognitive ability (Jaiswal et al., 2023).Mortality in severe infection is recorded by emitted larvae (Bruschi et al., 2002).Other symptoms encountered include numbness of limbs, depression, low oxygen supply to the brain focal neurologic deficits due to ischemic events due to larval migration and vascular obstruction, and lung inflammation due to helmintho-cytotoxity (Gentilini et al., 2011).

Conventional treatment of Trichinellosis:
There is no absolute effective treatment for the eradication of trichinellosis, as an effective treatment must combat different phases of the disease (Gottstein, et al., 2009;Albogami, 2023).Most anti-trichinellosis drugs have synergistic action by limiting inflammation and larval capsule formation (El-Wakil et al., 2023).Benzimidazole derivatives such as albendazole, flubendazole, and mebendazole are the foremost anthelmintic drugs used against trichinellosis (Codina et al., 2015).So far, these drugs may have a significant adverse impact on human health causing implication as cancer, encephalitis epilepsy, or even death (Matadamas-Martínez et al., 2013;Fahmy and Diab, 2021).In addition, some of these drugs are not advised during pregnancy and are suitable for toddlers (Shalaby et al., 2010).
Moreover, the efficiency of these regular drugs fluctuates depending on the phase of infection and time of drug application, the eradication power is more predominant during the early enteric phase as compared to the encysted muscular phase (Siriyasatien et al., 2003;Gottstein et al. 2009).Although albendazole is the most preferable drug against trichinellosis, it has a low water solubility, bioavailability, and tissue absorption and it shows weakened renitency against the encysted larvae stage (Kalaiselvan et al., 2007;Codina et al., 2015;Nada et al., 2018).Thus, the high demand for new and effective treatments against trichinellosis drugs is mandatory (Shalaby et al., 2010;Yadav et al., 2012).
To increase the rate of dissolution and oral bioavailability of albendazole, an assortment of approaches was used.Several therapeutic and alternative active compound strategies were used.This included the use of active compounds to enhance the drug's therapeutic efficacy and combat resistance (Eissa et al., 2022).Many studies were applied to enhance the efficacy of albendazole, the novel tested albendazole forms were found to eradicate the intestinal phase of T. spiralis infection and subsequently reduce its burden in muscle (García et al., 2013).Researchers assessed three new solid microencapsulated formulations of albendazole in vivo, aiming to surpass the oral bioavailability of standard albendazole.Two out of the three formulations were found to intensely reduce the parenteral phase measurement of the muscle larval (Codina et al., 2015).
Other methods were applied combining the drug into lipid-based drug delivery systems (Will Castro et al., 2021); and complexing the drug with cyclodextrin (Kalaiselvan et al., 2007 andEid et al., 2020).Essential oils are natural and complex mixtures of compounds from aromatic plant parts, in a study by Lopez et. al., (2022), carvacrol (a phenolic monoterpenoid in lots of essential oils) and albendazole combination were used to enhance the efficacy of albendazole.This strategy allowed to improve the efficacy of the treatment without increasing the administrative doses of albendazole or extending the treatment period which sequentially reduces the incidence of adverse effects (Krolewiecki et al., 2022).Another study demonstrated gallic acid in combination with albendazole has a promising antitrichinellosis effect against the muscular phase of T. spiralis larvae (Albogami, 2023).Albendazole-β-cyclodextrin citrate (ABZ: C-β-CD) complex also showed antiparasitic activity against T. spiralis in the parenteral phase in mice enhancing its efficacy (Codina et al., 2015).

New Anti-Trichinellosis Strategies:
The anti-trichinellosis strategy refers to innovative methods or approaches that are being developed or implemented to prevent, diagnose, or treat trichinellosis, which is an infectious disease caused by the parasite Trichinella.These strategies could include advancements in drug development, vaccine research, improved diagnostic techniques, vector control measures, public health interventions, or any other innovative means aimed at reducing the incidence or severity of trichinellosis infections.The goal is to introduce more effective and efficient methods to combat this parasitic disease and ultimately improve public health outcomes (Fig. 1).Consequently, many studies have investigated newer anthelminthic drugs derived from medicinal plants or with efficient antioxidant impact and low toxicity and adverse effects ( Yadav et al., 2012;Attia et al., 2015;Seow et al., 2021).The effects of myrrh extracted from the aloe-gum resin of Commiphora molmol were tested, and the results showed using myrrh for controlling T. spiralis could be promising and effective (Basyoni and El-Sabaa, 2013).Abuelenain et al. (2022) investigated the phenotypic changes induced by albendazole, Lipidium sativum (garden cress), and Commiphora molmol (myrrh), finding that myrrh surpassed garden cress as an effective complementary agent to albendazole in both in vivo and in vitro studies.
Punica granatum extract from a fruit commonly known as pomegranate showed anti-inflammatory and antioxidant properties that showed an anti-trichinellosis effect (Al-Megrin, 2017;Dkhil et al., 2019).Esmat et al. (2021) also stated that the P. granatum and amygdalin extracts with cobalamin when combined with albendazole can decrease larval pathology and myositis from T. spiralis.
The efficacy of the leaf extract of Lasia spinosa against T. spiralis was assessed and it was found that the extract decreased T. spiralis infections in mice.Therefore, the active ingredient of L. spinosa leaves needs to be isolated and tested against different stages of T. spiralis in animal models (Yadav et al., 2012).Also, the efficacy of Artemisia annua extract against trichinellosis was evaluated.The treatment declined T. spiralis adult-worm count in infected animals and reestablished the normal intestinal construction and diminished the pathological impact of the infection as edema, inflammation (El-Kady et al., 2022).The Curcuma longa extract, pomelo peels extract, and their chitosan NPs were used experimentally against trichinellosis in the presence of albendazole.This study mentioned that the NPs of Curcuma and Pomelo have the potential to be employed therapeutically in the treatment of trichinellosis.(El-Hamed et al., 2022).

Vaccination:
Long-term therapeutic investigations were conducted targeting T. spiralis, utilizing a novel cathepsin B gene (TsCB, GenBank: XP_003379650.1).The study explored the protective immunity induced by immunization with rTsCB in a mouse model.TsCB was identified in the cuticle and stichosome of the parasite.Vaccination with rTsCB triggered specific IgG and IgE responses, leading to partial immune protection.This was evidenced by a significant reduction in worm burden in the intestines and muscles of vaccinated mice.The humoral immune responses generated by rTsCB immunization impeded intestinal worm growth and compromised its fecundity.These findings suggest that TsCB could be considered a promising molecular target for the development of vaccines against T. spiralis infection (Cui et al., 2019).
T. spiralis galectin (Tsgal) is a recently discovered protein located on the surface of this nematode.The involvement of recombinant Tsgal (rTsgal) in the invasion of intestinal epithelial cells (IECs) by larvae has been observed, with the invasion process hindered by the presence of anti-rTsgal antibodies (Zhang et al., 2024).Vaccination with an oral rTsgal vaccine stimulated a local mucosal sIgA response in the gut, along with a specific systemic Th1/Th2 immune response, demonstrating clear protective immunity against T. spiralis challenge.The oral rTsgal vaccine presents a promising approach for controlling T. spiralis infection (Xu et al., 2022).
The biological properties of a novel T. spiralis trypsin (TsT) against larvae were assessed.TsT gene was recorded at T. spiralis lifecycle stages, principally at epicuticle of 5-6 day adult worms, indicating that TsT is a worm somatic antigen and adult-stage specific surface antigen.Inoculating mice with rTsT elicited a noticeable humoral immune response and stimulated the production of cytokines IFN-γ and IL-4.The mice that received the rTsT vaccination demonstrated a significant decrease of 33.17% in adult worms in the intestines and a 37.80% reduction in muscle larvae following larval challenge.These findings suggest that TsT could be regarded as a potential target antigen for developing anti-T.spiralis vaccines (Zhang et al., 2020).
In a research investigation, a recombinant Lactobacillus plantarum carrying the gene for T. spiralis inorganic pyrophosphatase (TsPPase) was utilized to assess its immune protective capabilities against T. spiralis infection.The findings revealed that the rTsPPase was successfully expressed on the surface of the recombinant strain, and oral vaccination with rTsPPase triggered elevated levels of specific serum IgG, IgG1, IgG2a, and mucosal secretory IgA (sIgA) in BALB/c mice (Hu et al., 2021).

Nanoparticles (NPs):
NPs are small-sized particles (10 to 100 nm) with high surface area to volume ratio, surface charge, crystalline and amorphous structures, shape, and color variety (Ealia et al., 2017;Mukherji et al., 2019).Nanostructures include polymers, liposomes, dendrimers, liposomes, and metal NPs (Ling et al., 2008).Different characterization methods are used to evaluate NPs as ultraviolet-visible (UV-vis) absorption spectroscopy, dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FT-IR), energy dispersive X-ray analysis, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) (Boroumand et al., 2019).Some NPs may be biodegradable, and non-toxic.NPs can be coated with organic particles as micelles and liposomes are known as nanocapsules and are commonly used in drug delivery systems due to their stability and size (Dash et al., 2020;Chandrakala et al., 2022).NPs can enhance the therapeutic competence of ionized drugs and increase the penetration of water-soluble compounds, proteins, peptides, vaccines, siRNA, miRNA, and DNA (Sperling & Parak, 2010).
The NPs have biomedical and pharmacological uses due to their antioxidant, antimicrobial, antidiabetic, and anticancer effects (Ameen et al., 2023;Baran et al., 2023;Meliani et al., 2023).Drug delivery systems using NPs are improved as compared to traditional forms of drugs (Chandrakala et al., 2022).NPs have been used to shield the drug in systemic circulation and limit its release to the selected sites (Yetisgin et al., 2020).Thus, the adverse side effects of the drug can be minimized, and the therapeutic efficacy is increased at lower doses of regular drugs (Zhang et al., 2020;Sana et al., 2022;Tabakoglu et al., 2023).
The efficacy of albendazole with albumin nanocarrier was introduced in two sizes; 10 nm which is extremely effective against tumor growth at low doses and 200 nm which has a good overwhelming ascites (Noorani et al., 2015).The oral bioavailability of albendazole was improved as a novel nanocrystalline formulation of the drug by spraydrying albendazole with a triblock copolymer.The new formula significantly enhanced the drug dissolution compared to the commercial product, and the formulation showed a good cyst inhibition effect 3.7-fold greater than that of regular albendazole (Hu et al., 2021).
Albendazole-encapsulated polyurethane nanoparticles were developed via the polycondensation technique which improved the shape and size of the drug (Eissa et al., 2022).The study exposed a noteworthy antiproliferative activity of the new nanoformula by apoptosis induction and cell death and the lack of toxicity as an indication of its possible biocompatible nanocarrier for anticancer drugs (Racoviceanu et al., 2020).It also assessed solid lipid nanoparticles containing albendazole to enhance cellular penetration and cytotoxicity against U-87 MG glioma cell lines.The findings demonstrated an enhanced efficacy of the drug when delivered through the nanocarrier (Marslin et al., 2017).Elmehy et al. (2021) reported that niosomes enhanced the efficacy of oral Ivermectin against various stages of T. spiralis infection compared to nano-crystalline Ivermectin.Both niosomes and nano-crystals caused a significant decrease in adult and larval counts with superior activity of niosomal Ivermectin by reduction of inflammation in both jejunal and muscle homogenates.Niosomal form efficacy exceeded the nanocrystalline form in the treatment of different phases of trichinellosis (Elmehy et al., 2021).
Nanomedicine is a highly significant application of nanotechnology that is used for the treatment, diagnosis, and control of various parasitic infections (Hasan, 2015;Khurana et al., 2019).Metal and metal oxide-based NPs are commonly categorized as inorganic NPs and they also have exceptional physical, chemical, and biological properties when compared to higher scales particles (Yu et al., 2021;Nair et al., 2022).Metal NPs such as Ag, Au, Ce, Fe, Se, Ti, and Zn possess an important role due to their unique bioactivities in nanoforms (Khurana et al., 2019;Malik et al., 2023).
Thus, The utilization of chitosan nanoparticles, either alone or loaded with full and half doses of albendazole, boosted its effectiveness against the muscular phases of T. spiralis infection, enhancing its antiparasitic activity (Mohammed et al., 2023).Muscle histological changes were also enhanced, and encysted larvae degeneration with minimum pathologic changes of infected skeletal muscles was also seen (Asif et al., 2023;Mohammed et al., 2023).
Also, the emerging anti-trichinosis using chemical and biosynthesized AgNPs revealed an obvious larvicidal effect against muscular larvae of Trichinella affecting their cuticle.The application of AgNPs led to the total suppression of infectivity in treated larvae exposed to sublethal doses of chemically and myrrh-prepared AgNPs before infecting animal models.This marks the inaugural instance where AgNPs synthesized with myrrh have been examined for their anthelminthic efficacy against Trichinella in vitro model (Abd- Elrahman et al., 2021).
Selenoproteins are proteins that can be found in archaea, bacteria, and eukarya There has been renewed interest in selenium NPs (SeNPs) as trichinosis supplements due to their incorporation in antioxidant defense systems-enzymes and proteins as Se-dependent glutathione peroxidase, thioredoxin-reductase, selenoprotein (Gabrashanska et al., 2019).
The addition of selenium as a supplement has the potential to hinder the generation of free radicals and the processes of lipid peroxidation in trichinellosis (Gabrashanska et al., 2010).The reduction of muscle larvae after Sel-plex application was 63%.The study indicated that a diet containing selenium may prove advantageous in managing diseases associated with significant oxidative stress, especially parasitic infections (Gabrashanska et al., 2019).

Conclusion
Many studies collectively contribute to a comprehensive understanding of trichinellosis pathogenesis and treatment modalities, paving the way for the development of effective interventions to combat this parasitic infection and alleviate its associated morbidity and mortality.The convergence of research efforts in parasitology, vaccine development, and nanotechnology offers hope for advancing our understanding of trichinellosis and developing more effective strategies for its prevention and treatment.