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After termination of a control program in 2004, Echinococcus granulosus infections have reemerged in Magallanes Region, Chile. Prevalence in sheep >2 years of age in 2023 resembled levels observed at the start of the program. Resurgence underscores the need for continued surveillance, particularly in younger sheep, to monitor recent transmission trends.

This study presents the first detection of Taenia omissa metacestodes in guanaco ( Lama guanicoe ) within the Chilean Patagonia, marking the southernmost record of natural infection in an intermediate host on the continent. Taenia omissa was found in the continental part of the Magallanes region where the top predators are pumas ( Puma concolor ). Conversely, all metacestodes found in guanacos collected from Tierra del Fuego Island, where no pumas exist, were identified solely as Echinococcus granulosus sensu stricto . Additionally, this research highlights a tissue preference of T. omissa for liver, contrasting with E. granulosus , which predominantly affects the lungs in guanacos. We also report the infection of T . pisiformis in 1 guanaco. Our findings emphasize the need for accurate identification of metacestodes during meat inspection in an area where T. omissa and E. granulosus overlap. This research also contributes to increase the knowledge of parasite–host dynamics in wildlife and underscores the importance of considering broader spectrum intermediate hosts in the epidemiology of parasitic infections.

Alveolar and cystic echinococcosis (AE, CE) caused by E. multilocularis and E. granulosus s.l., respectively, are considered emerging zoonotic diseases in Kyrgyzstan with some of the world highest regional incidences. Little is known regarding the molecular variability of both species in Kyrgyzstan. In this study we provide molecular data from a total of 72 parasite isolates derived from humans (52 AE and 20 CE patients) and 43 samples from dogs (23 infected with E. multilocularis and 20 with E. granulosus s.l.).Genetic variability in E. multilocularis was studied using the concatenated complete sequences of the cob, nad2 and cox1 mitochondrial genes adding a total of 3,558bp per isolate. The cob/nad2/cox1 A2 haplotype was identified in 63.4% of the human and in 65.2% of the dog samples. This haplotype was originally described in samples from Kazakhstan and St. Lawrence Island (Alaska, USA). We also describe here 16 non-previously defined variants of E. multilocularis (called A11-A26). All haplotypes cluster together within the Asian group in the haplotype network. Based on Fst values, low level of genetic differentiation was found between the populations of E. multilocularis isolated from different regions within the country. However, high degree of differentiation was found when all the concatenated sequences from Kyrgyzstan are considered as a single population and compared with the population of the parasite from the neighbouring country China. In the case of E. granulosus s.l. the analysis was based in 1,609bp of the cox1 gene. One isolate from a dog was identified as E. equinus, while all the other sequences were identified belonging to E. granulosus s.s. In total, 24 cox1 haplotypes of E. granulosus s.s. were identified including the already described variants: Eg01 (in 6 samples), Eg33 (in 4 samples), EgCl04 (in 2 samples), Eg03 (in 1 sample) and Eg32 (in 1 sample). From the twenty-five other isolates of E. granulosus s.s. a total of 19 non-previously described cox1 haplotypes were identified and named as EgKyr1 to EgKyr19. The most common haplotype infecting human is the EgKyr1 which was found in 5 isolates.The cob/nad2/cox1 A2 haplotype of E. multilocularis is responsible for the majority of human infections in Kyrgyzstan and is also found in the majority of dogs included in this study. Further similar studies in different parts of Asia could elucidate if it is also the most common variant infecting humans in other countries. It remains unknown if this particular haplotype presents differences in virulence which could have contributed to the emergency of alveolar echinococcosis in Kyrgyzstan. In the case of E. granulosus s.s. it seems that there is no dominant haplotype infecting humans in Kyrgzstan. Further characterization of biological or antigenic features of dominant mitochondrial haplotypes could help to elucidate if they present differences which could be relevant in the diagnostic, pathogenicity or in the host/parasite interaction when infecting humans.

We report a case of Dirofilaria immitis nematode infection in a dog imported from Venezuela that had been living for 2 years in Santiago, Chile, where this parasite had not been reported before. Our findings warrant surveillance for all dogs imported to Chile, given that suitable conditions exist for establishing this parasite.

Most human cystic echinococcosis (CE) cases worldwide are attributed to Echinococcus granulosus sensu stricto (s.s), followed by the G6 and G7 genotypes. While E. granulosus s.s. has a cosmopolitan distribution, the G6 genotype is restricted to areas where camels and goats are present. Goats are the primary livestock in the Neuquén province in Argentina where the G6 genotype has been reported to be responsible for a significant percentage of CE human cysts genotyped. In the present study, we genotyped 124 Echinococcus cysts infecting 90 CE-confirmed patients. Echinococcus granulosus s.s. was identified in 51 patients (56.7%) with 81 cysts and the G6 genotype in 39 patients (43.3%) harbouring 43 cysts. Most CE cases ≤18 years were male suggesting pastoral work could be a risk factor for the infection. Echinococcus granulosus s.s. was significantly found more frequently in the liver (32/51 patients) and the G6 genotype in the lungs and extrahepatic localizations (27/39). The patients infected with E. granulosus s.s., presented up to 6 cysts while patients infected with G6 presented a maximum of 2. The diameter of lung cysts attributed to E. granulosus s.s. was significantly larger compared to lung cysts from G6. Following the WHO ultrasound classification of liver cysts, we observed inactive cysts in 55.6% of G6 cysts and only 15.3% of E. granulosus s.s cysts. In conclusion, we provide evidence of differences in clinical aspects of CE caused by E. granulosus s.s. and the G6 genotype of E. granulosus s.l. complex infecting humans.

Cystic echinococcosis (CE) is a public health problem in livestock-breeding areas, including Chile, which adhered to the Pan American Health Organization Regional Program for the Elimination of CE 2020-2029. Abdominal ultrasound (US) screening of school-aged children (SAC) in high-risk areas is envisaged by the Action Plan for Control, Monitoring and Prevention of CE of the Ministry of Health (MoH) of Chile. We implemented pilot US screening and estimated CE prevalence in SAC in three municipalities prioritized by the MoH, to inform about the feasibility of targeting this age group within the activities of the Action Plan. A cross-sectional US screening was carried out in SAC (6-14 years) in Río Hurtado (Coquimbo region), Paillaco (Los Ríos), and Chile Chico (Aysén) municipalities. CE was diagnosed according to the WHO-IWGE recommendations. A total of 873 SAC were screened over 10 working days, with excellent participation (81-93%). Three children had hepatic CE cysts (3/873; 0.3%); the highest prevalence was found in Chile Chico (0.6%, 95% CI 0.2%-2.2%). US screening in SAC is technically feasible in Chile. While prevalence of CE in SAC might be too low to allow school-based monitoring and evaluation of a structured control program, US screening in SAC could allow early case-finding and support the implementation of control measures around new diagnoses.

This study investigates the genetic variability of in black rats ( ), a common tapeworm that infects cats and rodents worldwide. Despite its widespread presence and zoonotic potential, little is known about the genetic diversity of this parasite in the Americas. We conducted DNA barcoding analysis using mitochondrial 1 gene sequences using samples collected from 171 invasive wild black rats, captured in the temperate rainforest of Southern Chile. We also included two adult parasites isolated from road killed Kodkods ( ), a small felid species native to the Americas. Our findings revealed only two haplotypes, suggesting low genetic variability in a parasite that arrived in the Americas with the Spanish colonization. These haplotypes are more closely related to parasite populations from Peru, Africa, Australia, and Europe, suggesting an origin linked to the Spanish colonization, possibly from North Africa via the Canary Islands. The study also analyzed infection rates, parasite size, and their correlation with host body size, age, and weight, revealing significant patterns. These results provide new insights into the biogeography and genetic diversity of . in a new geographical area, enhancing our understanding of its evolutionary history.

The detection of Echinococcus multilocularis in infected canids and the environment is pivotal for a better understanding of the epidemiology of alveolar echinococcosis in endemic areas. Necropsy/sedimentation and counting technique remain the gold standard for the detection of canid infection. PCR-based detection methods have shown high sensitivity and specificity, but they have been hardly used in large scale prevalence studies. Loop-mediated isothermal amplification (LAMP) is a fast and simple method to detect DNA with a high sensitivity and specificity, having the potential for field-application. A specific LAMP assay for the detection of E. multilocularis was developed targeting the mitochondrial nad1 gene. A crucial step for amplification-based detection methods is DNA extraction, usually achieved utilising silica-gel membrane spin columns from commercial kits which are expensive. We propose two cost-effective and straightforward methods for DNA extraction, using NaOH (method 1A) and InstaGeneTM Matrix (method 1B), from isolated eggs circumventing the need for commercial kits. The sensitivity of both assays with fox samples was similar (72.7%) with multiplex-PCR using protocol 1A and LAMP using protocol 1B. Sensitivity increased up to 100% when testing faeces from 12 foxes infected with more than 100 intestinal stages of E. multilocularis. For dogs, sensitivity was similar (95.4%) for LAMP and multiplex-PCR using protocol 1B and for both methods when DNA was extracted using protocol 1A (90.9%). The DNA extraction methods used here are fast, cheap, and do not require a DNA purification step, making them suitable for field studies in low-income countries for the prevalence study of E. multilocularis.

Different helminths and protozoa are transmitted to humans by oral uptake of environmentally resistant parasite stages after hand-to-mouth contact or by contaminated food and water. The aim of this study was to develop and validate a method for the simultaneous detection of parasite stages from fresh produce (lettuce) by a one-way isolation test kit followed by genetic identification (PCR, sequencing). Three sentinel zoonotic agents (eggs of Toxocara canis, Echinococcus multilocularis and oocysts of Toxoplasma gondii) were used to investigate the practicability and sensitivity of the method. The detection limits (100% positive results) in the recovery experiments were four Toxocara eggs, two E. multilocularis eggs and 18 T. gondii oocysts (in 4/5 replicates). In a field study, helminth DNA was detected in 14 of 157 lettuce samples including Hydatigera taeniaeformis (Syn. Taenia taeniaeformis) (four samples), T. polyacantha (three), T. martis (one), E. multilocularis (two) and Toxocara cati (four). Toxoplasma gondii was detected in six of 100 samples. In vivo testing in mice resulted in metacestode growth in all animals injected with 40–60 E. multilocularis eggs, while infection rates were 20–40% with 2–20 eggs. The developed diagnostic strategy is highly sensitive for the isolation and genetic characterisation of a broad range of parasite stages from lettuce, whereas the sensitivity of the viability tests needs further improvement.

Climate change, competent vectors, and reservoir animals are the main factors for developing vector-borne zoonotic diseases. These diseases encompass a significant and widespread category of pathogens (e.g., viruses, bacteria, protozoa, and helminths) transmitted by blood-feeding arthropods, including ticks, fleas, lice, triatomines, mosquitoes, sandflies, and blackflies. In Chile, several studies have explored the role of dogs as reservoirs of vector-borne pathogens; however, there is a lack of research investigating the presence of pathogens in arthropods. Specifically, within the order Diptera, limited knowledge exists regarding their roles as carriers of pathogens. This study aimed to examine the presence of zoonotic filarial nematodes in mosquitoes and dogs within a previously unstudied semi-rural area of Central Chile. Two hundred samples of dog blood and seven hundred and twenty-four mosquitoes were collected during 2021–2022 and studied for filarial nematodes by PCR. The prevalence of microfilaremic dogs detected by Knott’s test was 7.5%, with Acanthocheilonema reconditum being the only species identified. Aedes ( Ochlerotatus ) albifasciatus was the most abundant mosquito species collected, and 15 out of 65 pools were positive for filarial nematodes. Among these pools, 13 tested positive for Acanthocheilonema reconditum , and two tested positive for Setaria equina through PCR. Additionally, five Culex pipiens specimens were positive for Acanthocheilonema reconditum . Despite the absence of zoonotic filarial species, these findings underscore the significance of monitoring pathogens in mosquitoes and animal hosts and continued research into the dynamics of vector-borne diseases, particularly in unexplored regions.