**4. Human outbreaks due to non-encapsulated** *Trichinella* **species**

Only *T. pseudospiralis* and *T. papuae* have been related to human outbreaks to date, while *T. zimbawensis* has not been associated to any such outbreaks. **Figure 7** represents the different outbreaks. Before the first outbreak in Kamchatka, only one case of *T. pseudospiralis* had been discovered in New Zealand [46, 63]. According to Edoardo Pozio, there were no species-specific primers available at the time of the outbreaks, therefore the species could have been *T. papuae* in the case of the Thai outbreak [47] but it had not been discovered yet [11]. The larvae were first isolated in a laboratory and then identified using cross-breeding procedures in the context of the Kamchatka epidemic [63]. Species-specific primers were utilised in the case of the French outbreak [11, 48]. The majority of outbreaks caused by *Trichinella Papuae* have occurred in Thailand, usually caused by the consumption of wild raw pig flesh [49, 50, 52]. In Taiwan, one outbreak was caused by the ingestion of soft-shelled turtles [51]. The most common clinical signs in these epidemics were myalgia, facial oedema and fever. The levels of creatine phosphokinase and aspartate aminotransferase were likewise higher. A few muscle biopsy specimens also included larvae [53]. These outbreaks suggest that there is a strong link between parasites and human behaviour, particularly the eating habits and certain rituals, such as the 'mumu' cooking method in Morehead District, PNG, which could have been a source of *T. papuae* infection [46, 64]. Albendazole, glucocorticosteroids and various supportive medications such as painkillers are generally used in the treatment [65]. A study found that the maslinic acid's efficiency in rats


#### **Table 4.**

*Outbreaks caused due to different non-encapsulated* Trichinella *species.*

was comparable to that of fenbendazole, with no side effects, indicating that it could be a promising anthelminthic drug against *Trichinella* larvae (**Table 4**) [76].

### **4.1 Species identification methods**

A polymerase chain reaction-based on the mitochondrial large subunit ribosomal RNA gene was paired with a pyrosequencing technique to distinguish the four *Trichinella* species, this was successfully found to be sensitive enough to identify the individual larvae [77]. PCR based on the ITS1, ITS2 and ESV regions has also been utilised for the molecular identification of the species among wildlife in South Africa [78]. FRET-PCR and a melting curve analysis have also been utilised for the differential detection of the species [79]. Using Western blot, *T. pseudospiralis* infection can be differentiated from *T. spiralis* or *T. britovi* infection. When the source is unknown, this technique may be beneficial in epidemiological investigations [80].
