Pathological characteristics of Linguatula serrata (aberrant arthropod) infestation in sheep and factors associated with prevalence in Iran

Prevalence and risk factors of Linguatula spp. in slaughter animals in Tabriz, Iran, and methods for nymphal stage inactivation

Linguatula is a food born zoonotic parasite in which carnivores and herbivores serve as final and intermediate hosts, respectively. Human infection with Linguatula spp. occurs following consumption of raw or undercooked infected internal organs of the intermediate host and/or consumption of water and/or vegetables contaminated with eggs released from final hosts. The aim of this study was to determine prevalence and risk factors of Linguatula spp. in sheep, cattle, buffalo, goats and camels slaughtered at the Tabriz abattoir, Iran. In addition, effect of temperature and sodium chloride (NaCl) on survival time of Linguatula spp. nymphs was assessed. For this purpose, 25,520 mesenteric lymph nodes from 2552 animals and the livers and lungs from 656 animals were collected randomly and examined. To evaluate the effect of temperature and NaCl on the survival of Linguatula spp. nymphs in infected livers and lungs, 30 g of each liver and lung with dimensions of 2 × 3 × 4 cm, were exposed to temperatures of -20, 10, 50, 60 and 72 °C and NaCl concentrations of 5 %, 10 %, 15 % and 20 % for 3, 6, 12, 24, 48 and 72 h, in triplicate. Based on the mesenteric lymph nodes, 25.7 % (656 of 2552 animals) were infected with Linguatula spp. Of the 656 liver and lungs assessed, 141 (21.5 %) and 62 (9.5 %) were infected with Linguatula spp., respectively. The rate of infection of mesenteric lymph nodes in all animals was significant with age (P < 0.05), with more older animals infected. In regards to sex, except for camels, more female animals were infected than male animals (P < 0.05). There was a significant difference in survival of nymphs based on temperature and/or NaCl and time (P < 0.0001). At 72 h, all temperatures assessed except 10 °C, resulted in all nymphs being inactivated. Sodium chloride was more effective against Linguatula spp. nymphs in livers than in lungs with 100 % efficacy only achieved against nymphs in livers at 20 % concentration after 48 h and at 10 and 15 % concentration after 72 h. Based on these results, heating and application of common salt as a food preservative in meat products reduces the survival time of Linguatula spp. nymphs and their use could decrease the risk of food-born microorganisms.

Characterization of the Tongue Worm, Linguatula serrata (Pentastomida), Identified from Hares (Lepus europaeus) in Romania

Linguatula serrata (Frölich, 1789) is a widespread parasite known as the tongue worm belonging to the family Linguatulidae. The adult form of the parasite is usually located in the upper respiratory tract of domestic and wild carnivores while the larval forms are located in the visceral organs of intermediate hosts (various herbivorous mammals). Twenty-four European brown hares (Lepus europaeus) were examined in this study, of which two were positive with L. serrata nymphs. The collected nymphs were examined morphologically using electron-microscopic analysis and molecularly by amplification of 18S rRNA and COX1 genes. Lung tissue samples were also collected and histopathological examination was performed. Histopathological examination revealed the following lesions: generalized inflammatory oedema, granulomas with necrosis, calcification and fibrosis in the bronchial tree. The results of molecular sequencing for L. serrata specimens collected from the European brown hares are deposited in GenBank. This study presents the first report on Linguatula serrata nymphs collected from L. europaeus in Romania, using molecular and morphological characterization simultaneously.

Prevalence of Linguatula sp., a food-borne zoonotic aberrant arthropod, in river buffaloes slaughtered at Tabriz slaughterhouse, Iran

BACKGROUND

Canids and herbivores are the definitive and intermediate hosts of Linguatula sp., respectively.

METHODS

Mesenteric lymph nodes (n=32 525) were randomly collected from 7585 buffaloes from July 2016 to July 2019 and examined macroscopically.

RESULTS

Results showed that 388 (5.11%) buffaloes were infected. The intensity of infection was determined to be 3.07±0.07. Significant statistical association was identified between infection rate and age and sex. Although there were no significant differences in the infection rate over different seasons, the highest infection rate was observed in autumn.

CONCLUSIONS

These data highlight the importance of inspection at slaughter.

Linguatula serrata in cattle in southeastern Iran: Epidemiological, histopathological and phylogenetic profile and its zoonotic importance

This study aimed to determine the prevalence, histopathological observations, and phylogenetic analysis of L. serrata in cattle and its potential zoonotic and public health implications in southeastern Iran.The cross-sectional study was performed in cattle in southeastern Iran. Lymph nodes were collected from each cattle and examined by parasitological and histopathological techniques. A binary logistic regression and chi-square tests were implemented to analyze the data. Genomic DNA was randomly extracted from the nymphal stages of Linguatula isolates. Further characterization and phylogenetic relationships were done using two primers for amplification of partial DNA fragments of 18 s rRNA and cytochrome C oxidase subunit 1 (cox1), respectively.The results showed that 64 cattle of the total 404 were infected with L. serrata. There was no significant difference between linguatulosis infection and gender, while age was significantly different (P < 0.05). The cyst-like spaces containing the longitudinal and transverse sections of the L. serrata nymphs were surrounded by granulomatous reactions. The higher nucleotide variation in the cox1 region was supported by estimating the evolutionary divergence between L. serrata isolates and other Linguatula records of ruminants in Iran. The phylogenetic tree confirmed the close evolutionary relationships among all reported records of L. serrata in Iran.The high prevalence of linguatulosis caused by L. serrata declares the existence of a potential risk of FBPs for humans in southeastern Iran. This condition can advance more serious public health problems and requires a comprehensive control program and treatment strategies to prevent the disease.