High-resolution prediction models for Rhipicephalus microplus and Amblyomma cajennense s.l. ticks affecting cattle and their spatial distribution in continental Ecuador using bioclimatic factors.

In Ecuador, the main tick species affecting cattle are Rhipicephalus microplus and Amblyomma cajennense sensu lato. Understanding their spatial distribution is crucial. To assess their distribution, data from 2895 farms visited between 2012 and 2017 were utilized. Ticks were collected during animal inspections, with each farm's location georeferenced. Bioclimatic variables and vapor pressure deficit data were obtained from Climatologies at High resolution for the Earth´s Land Surface Areas (CHELSA) dataset. They were overlaid to develop predictive maps for each species using Random Forest (RF) models. The cross-validation results for RF prediction models showed high accuracy for both R. microplus and A. cajennense s.l. presence with values of accuracy = 0.97 and 0.98, sensitivity = 0.96 and 0.99, and specificity = 0.96 and 0.93, respectively. A carefully selected subset of bioclimatic variables was used to describe the presence of each tick species. Higher levels of precipitation had positive effect on the presence of R. microplus but a negative effect on A. cajennense s.l. In contrast, isothermality (BIO3) was more important for the presence of A. cajennense s.l. compared to R. microplus. As a result, R. microplus had a broader distribution across the country, while A. cajennense s.l. was mainly found in coastal areas with evident seasonality. The coexistence of both species in some regions could be attributed to transitional zones, whereas high altitudes limited tick presence. This information can aid in developing appropriate tick management plans, particularly considering A. cajennense s.l.'s broad host range species and R. microplus's specificity for cattle. Moreover, the predictive models can identify areas at risk of associated challenging hemoparasite, requiring special attention and mitigation measures.

Systematics and geographical distribution of Galba species, a group of cryptic and worldwide freshwater snails.

Cryptic species can present a significant challenge to the application of systematic and biogeographic principles, especially if they are invasive or transmit parasites or pathogens. Detecting cryptic species requires a pluralistic approach in which molecular markers facilitate the detection of coherent taxonomic units that can then be analyzed using various traits (e.g., internal morphology) and crosses. In asexual or self-fertilizing species, the latter criteria are of limited use. We studied a group of cryptic freshwater snails (genus Galba) from the family Lymnaeidae that have invaded almost all continents, reproducing mainly by self-fertilization and transmitting liver flukes to humans and livestock. We aim to clarify the systematics, distribution, and phylogeny of these species with an integrative approach that includes morphology, molecular markers, wide-scale sampling across America, and data retrieved from GenBank (to include Old World samples). Our phylogenetic analysis suggests that the genus Galba originated ca. 22 Myr ago and today comprises six species or species complexes. Four of them show an elongated-shell cryptic phenotype and exhibit wide variation in their genetic diversity, geographic distribution, and invasiveness. The remaining two species have more geographically restricted distributions and exhibit a globose-shell cryptic phenotype, most likely phylogenetically derived from the elongated one. We emphasize that no Galba species should be identified without molecular markers. We also discuss several hypotheses that can explain the origin of cryptic species in Galba, such as convergence and morphological stasis.

Monitoring treatment of Taenia solium- neurocysticercosis by detection of circulating antigens: a case report.

BACKGROUND: Parenchymal neurocysticercosis is a frequent cause of seizures in areas endemic for Taenia solium. At present there is scarce data on the evolution of the levels of circulating metacestodal antigen before, during and after treatment with anthelmintic drugs. CASE PRESENTATION: A patient with paucisymptomatic neurocysticercosis (NCC) diagnosed by Ag-ELISA, and confirmed by MRI images, was treated with praziquantel, albendazole and dexamethasone. The level of circulating T. solium antigen was determined weekly. Circulating antigen disappeared from his blood within 14 days after the start of the treatment and correlated with the involution of the cysticerci in the brain shown by imaging. Seventeen years later, the patient has not shown any side effect nor symptoms related to the treatment or to NCC. CONCLUSIONS: If this encouraging finding is confirmed in a larger series of patients, this technique could be used to determine parasitological cure after treatment and might complement or sometimes replace sequential MRI-imaging of the brain.

The unexpected discovery of Brucella abortus Buck 19 vaccine in goats from Ecuador underlines the importance of biosecurity measures.

Very few, mostly old, and only preliminary serological studies of brucellosis in goats exist in Ecuador. In order to assess the current epidemiological situation, we performed a cross-sectional serological study in the goat populations of Carchi (n = 160 animals), Pichincha (n = 224 animals), and Loja provinces (n = 2024 animals). Only two positive serological results (RB negative and SAT-EDTA ≥400 IU/ml) were obtained in lactating goats from the same farm in Quito (Pichincha province). Additionally, milk was sampled from 220 animals in Pichincha province. The present study indicates a low apparent prevalence in Pichincha province and absence in Carchi and Loja provinces. A total of 25 positive milk ring tests (MRT) were obtained in Pichincha province yielding a prevalence of MRT of 11.16%. Subsequent culture was performed on the positive MRT samples. All results were negative, apart from a single sample, obtained from a serologically positive goat in Quito, that was positive for Brucella abortus strain 19 (B19). Several hypotheses are forwarded concerning this unexpected result. The most likely hypothesis is the possible accidental use of a needle, previously used for vaccination of cattle with the said vaccine, for the administration of drug treatment to the goat. This hypothesis underlines the necessity of biosecurity measures to prevent this type of accidents.

Molecular analyses reveal two geographic and genetic lineages for tapeworms, Taenia solium and Taenia saginata, from Ecuador using mitochondrial DNA.

Tapeworms Taenia solium and Taenia saginata are the causative agents of taeniasis/cysticercosis. These are diseases with high medical and veterinary importance due to their impact on public health and rural economy in tropical countries. The re-emergence of T. solium as a result of human migration, the economic burden affecting livestock industry, and the large variability of symptoms in several human cysticercosis, encourage studies on genetic diversity, and the identification of these parasites with molecular phylogenetic tools. Samples collected from the Ecuadorian provinces: Loja, Guayas, Manabí, Tungurahua (South), and Imbabura, Pichincha (North) from 2000 to 2012 were performed under Maximum Parsimony analyses and haplotype networks using partial sequences of mitochondrial DNA, cytochrome oxidase subunit I (COI) and NADH subunit I (NDI), from Genbank and own sequences of Taenia solium and Taenia saginata from Ecuador. Both species have shown reciprocal monophyly, which confirms its molecular taxonomic identity. The COI and NDI genes results suggest phylogenetic structure for both parasite species from south and north of Ecuador. In T. solium, both genes gene revealed greater geographic structure, whereas in T. saginata, the variability for both genes was low. In conclusion, COI haplotype networks of T. solium suggest two geographical events in the introduction of this species in Ecuador (African and Asian lineages) and occurring sympatric, probably through the most common routes of maritime trade between the XV-XIX centuries. Moreover, the evidence of two NDI geographical lineages in T. solium from the north (province of Imbabura) and the south (province of Loja) of Ecuador derivate from a common Indian ancestor open new approaches for studies on genetic populations and eco-epidemiology.

Widespread acaricide resistance and multi-resistance in Rhipicephalus microplus in Ecuador and associated environmental and management risk factors.

Rhipicephalus microplus is a cattle tick widely distributed in tropical and subtropical areas. Various acaricides are used and applied to control the ticks, but resistance is common. The objectives of this study were to evaluate the spatial distribution of resistance to the most commonly applied acaricides (amitraz, ivermectin, and alpha-cypermethrin) in ticks and assess potential risk factors associated with tick resistance in a strip between ±0.5° latitude of the continental part of Ecuador. Larval package tests were used to evaluate the level of acaricide resistance in 96 cattle farms. The association between 11 farm management and 8 ecological variables and acaricide resistance and multi-resistance was evaluated. Dose-response models were used to study the level of resistance. 72 % (69/96), 70 % (67/96), and 64 % (61/96) of farms had ticks resistant to amitraz, ivermectin, and alpha-cypermethrin, respectively. Multi-resistance was also widespread. Larger herds and dairy farms had a significantly higher probability of resistance for three commonly used acaricides. Environmental factors related to rainfall were also associated with acaricidal resistance presence. Ivermectin resistance was associated with use of the acaricide (OR = 8.9909; 7.7519-10.2300), mean temperature (OR = 1.3205;1.0742-1.6799)), and inversely associated with paddock rotation (OR = 0.1753; 0.0294-0.7836), and precipitation of the wettest month (BIO13) (OR = 0.9903; 0.9839-0.9957); amitraz with use of the acaricide (OR = 4.3934; 3.3679-5.4188), precipitation seasonality (BIO15) (OR=0.9742; 0.9542-0.9925), and precipitation (OR = 0.9995; 0.9994-0.9999); and alpha-cypermethrin with precipitation (OR=0.9995; 0.9990-0.9999) and use of the acaricide (OR = 14.4597; 13.4343-15.4852). In conclusion, acaricide resistance was widespread in our study area. Better-integrated tick management and environmentally friendly control strategies are required to reduce the use of acaricides while limiting tick-associated damage in herds.

Drivers and evolution of acaricide resistance and multi-resistance in two Ecuador's subtropical livestock farming areas.

The management of cattle ticks, particularly Rhipicephalus microplus, poses a global challenge in subtropical regions like Ecuador due to its impact on meat and milk productivity, leading to economic losses. Misuse of acaricides has resulted in resistance and multi-resistance, diminishing their effectiveness. This study evaluated resistance to amitraz, alpha-cypermethrin, and ivermectin using the Larval Packet test, laboratory-reared tick larvae collected from cattle were tested. Data on farm management and tick control practices were gathered via a questionnaire in Northwest Pichincha and Quijos River Valley over two years. Resistance rates in the first year (2020-2021) were 67.21% for amitraz, 57.38% for ivermectin, and 67.21% for alpha-cypermethrin. One year later (2021-2022), resistance levels were 59.57% for amitraz, 57.45% for ivermectin, and 68.09% for alpha-cypermethrin, with multi-resistance rates at 67.21% and 65.96% respectively. No significant differences were found between years or locations. Analysis of larval survival data determined lethal doses for tested acaricides. The study emphasizes the association between the lack of acaricide rotation, the incorrect dosage, and the absence of non-chemical measures in tick management could be associated with the development of resistances in ticks. Likewise, this study promotes the need for collaborative efforts to improve control practices and maintain acaricide efficacy.

Bayesian modelling to estimate the test characteristics of coprology, coproantigen ELISA and a novel real-time PCR for the diagnosis of taeniasis.

OBJECTIVE: To estimate and compare the performances of coprology, copro-Ag ELISA and real-time polymerase chain reaction assay (copro-PCR) for detection of Taenia solium tapeworm carriers. METHODS: The three diagnostic tests were applied on 817 stool samples collected in two Zambian communities where taeniasis is endemic. A Bayesian approach was used to allow estimation of the test characteristics. Two (0.2%; 95% Confidence Interval (CI): 0-0.8), 67 (8.2%; 95% CI: 6.4-10.3) and 10 (1.2%; 95% CI: 0.5-2.2) samples were positive using coprology, copro-Ag ELISA and copro-PCR, respectively. RESULTS: Specificities of 99.9%, 92.0% and 99.0% were determined for coprology, copro-Ag ELISA and copro-PCR, respectively. Sensitivities of 52.5%, 84.5% and 82.7% were determined for coprology, copro-Ag ELISA and copro-PCR, respectively. CONCLUSIONS: We urge for additional studies exploring possible cross-reactions of the copro-Ag ELISA and for the use of more sensitive tests, such as copro-PCR, for the detection of tapeworm carriers, which is a key factor in controlling the parasite in endemic areas.

Case report: First report on human infection by tick-borne Babesia bigemina in the Amazon region of Ecuador.

Babesiosis is a protozoan disease acquired by the bite of different species of ticks. More than 100 Babesia spp. infect wild and domestic animals worldwide, but only a few have been documented to infect humans. Generally, babesiosis is asymptomatic in immunocompetent persons; however, in immunocompromised can be life-threatening. A 13-year-old boy from the Amazon region presented with a 3-month evolution of fever, chills, general malaise, and arthralgia accompanied by anemia and jaundice. In the last 4 years was diagnosed with chronic kidney failure. By nested-PCR using 18S RNA ribosomal gene as target and DNA sequencing, the phylogenetic analysis showed Babesia bigemina as the causative agent in the blood. Treatment with oral quinine plus clindamycin for six continuous weeks was effective with no relapse occurring during 12 months of follow-up. This is the second human case in Ecuador but the first caused by the zoonotic B. bigemina which confirms the existence of active transmission that should alert public health decision-making authorities on the emergence of this zoonosis and the need for research to determine strategies to reduce tick exposure.

An economic evaluation of cattle tick acaricide-resistances and the financial losses in subtropical dairy farms of Ecuador: A farm system approach.

Estimates of economic losses in cattle due to tick infestations in subtropical areas are limited, such as in Ecuador. Ticks affect animal production and health, but those direct effects are difficult to estimate since financial exercises carried out in farms consider both costs of the inputs and revenues. This study aims to quantify the costs of inputs involved in milk production and to know the role of acaricide treatment in the production costs on dairy farms in subtropical zones using a farming system approach. Regression and classification trees were used to study the relationship between tick control, acaricide resistance and the presence of high level of tick infestation in the farm system. Even though there was no significant direct association between high levels of tick infestation and the presence of acaricide resistance in ticks, a more complex structure for resistances operates in the manifestation of high tick infestation involving levels of farm technology and no acaricide resistance. Farms with higher levels of technology allocate a lower percentage of sanitary expenses to control ticks (13.41%) in comparison to semi-technified (23.97%) and non-technified farms (32.49%). Likewise, more technified and bigger herds have a lower annual expenditure on acaricide treatment (1.30% of the production budget equivalent to 8.46 USD per animal) compared to non-technified farms where it can represent more than 2.74% of the production budget and where the absence of cypermethrin resistance increases the treatment cost to 19.50 USS per animal annually. These results can motivate the development of information campaigns and control programmes targeted to the reality of small and medium farms that are the most affected in terms of the money they invest in controlling ticks.

The Associated Decision and Management Factors on Cattle Tick Level of Infestation in Two Tropical Areas of Ecuador.

Decision-making on tick control practices is linked to the level of knowledge about livestock farming and to the social context in which individuals practice them. Tick infestation is one of the main problems in tropical livestock production. The objective of this study was to characterize tick-control related practices in two tropical livestock areas and their potential association with the level of tick infestation. A total of 139 farms were included in this survey. To determine this association, a multivariate logistic regression model was used. A stepwise model selection procedure was used and model validation was tested. Cattle husbandry as a main activity, the use of external paddocks, the use of amitraz, and the lack of mechanization on the farm were related with high tick infestation. On the other hand, owner involvement in the preparation of acaricide solution was identified as a protective factor against high tick infestation. At animal level, age (old), body condition status (thin), and lactation were also associated with high tick infestations, while Bos primigenius indicus cattle and their crosses reduced the probability of high tick infestations. The factors studied, such as herd size, education level of the owners, and veterinary guidance, varied from farm to farm. Nonetheless, these differences did not generate changes in the level of tick infestation. According to the area under the receiver operating characteristic curve (AUC-ROC), the model at farm level predicts a high level of infestation, with an accuracy of 72.00% and high sensitivity. In addition, at animal level, crossbreeding with indicus cattle and breeding selection for host resistance will be useful against high tick infestation. Likewise, the implementation of programs of capacitation and research on tick control for farmers, cowboys, and vets in these areas is necessary.

Widespread resistance to macrocyclic lactones in cattle nematodes in Ecuador.

The aim of the present study was to assess the resistance status of bovine gastrointestinal nematodes (GINs) against ivermectin (IVM) and fenbendazole (FBZ) in Ecuador. The study involved five cattle farms located in different topographic zones of the country. Anthelmintic efficacy was assessed by calculating the percentage of fecal egg counts reduction (FECR) after treatment. Additionally, DNA from pooled larval cultures was screened to ascertain benzimidazole resistance alleles. For animals treated with IVM, FECR percentages ranged from 0 to 68%, indicating the presence of highly resistant worms. The opposite was found for animals treated with FBZ, where FECR percentages were above 90% on all the farms tested. Pooled coprocultures revealed that Cooperia spp. were the predominant species pre and post-treatment although minor proportions of Haemonchus spp. and Ostertagia spp. were also identified. No mutations conferring resistance to benzimidazoles were identified in the beta-tubulin isotype 1 gene of the isolated Cooperia spp. worms, which is in line with the results of the FECR performed with FBZ. Overall, the present study highlights widespread resistance of bovine GINs to IVM but no to FBZ in Ecuador.

Human myiasis in Ecuador.

We review epidemiological and clinical data on human myiasis from Ecuador, based on data from the Ministry of Public Health (MPH) and a review of the available literature for clinical cases. The larvae of four flies, Dermatobia hominis, Cochliomyia hominivorax, Sarcophaga haemorrhoidalis, and Lucilia eximia, were identified as the causative agents in 39 reported clinical cases. The obligate D. hominis, causing furuncular lesions, caused 17 (43.5%) cases distributed along the tropical Pacific coast and the Amazon regions. The facultative C. hominivorax was identified in 15 (38%) clinical cases, infesting wound and cavitary lesions including orbital, nasal, aural and vaginal, and occurred in both subtropical and Andean regions. C. hominivorax was also identified in a nosocomial hospital-acquired wound. Single infestations were reported for S. haemorrhoidalis and L. eximia. Of the 39 clinical cases, 8 (21%) occurred in tourists. Ivermectin, when it became available, was used to treat furuncular, wound, and cavitary lesions successfully. MPH data for 2013-2015 registered 2,187 cases of which 54% were reported in men; 46% occurred in the tropical Pacific coast, 30% in the temperate Andes, 24% in the tropical Amazon, and 0.2% in the Galapagos Islands. The highest annual incidence was reported in the Amazon (23 cases/100,000 population), followed by Coast (5.1/100,000) and Andes (4.7/100,000). Human myiasis is a neglected and understudied ectoparasitic infestation, being endemic in both temperate and tropical regions of Ecuador. Improved education and awareness among populations living in, visitors to, and health personnel working in high-risk regions, is required for improved epidemiological surveillance, prevention, and correct diagnosis and treatment.

Prevalence of Fasciola hepatica infection in Galba cousini and Galba schirazensis from an Andean region of Ecuador.

Some Lymnaeid snails are intermediate hosts of the liver fluke Fasciola hepatica, the causal agent of fasciolosis, a zoonotic parasitic disease. Human and livestock fasciolosis has been reported in a highland community located in the Chimborazo Province of the Ecuadorian Andes. However, no previous study has been carried out to identify which snail species act as intermediate host/s of F. hepatica. This study first aimed to identify the intermediate snail species and secondly to determine the prevalence of natural infection with F. hepatica in 230 lymnaeid snails sampled from irrigation and drainage canals in this area. The first objective entailed observations of shell morphology and internal organs as well as sequencing of the cytochrome oxidase subunit 1 (COI) gene. For the second objective, we used classic parasitological methods (observation of rediae and cercarial emission) and PCR amplification specie-specific to F. hepatica. COI haplotype networks were built to elucidate phylogeographic relationships between the snail populations from this highland community with other American and worldwide populations. We identified two lymnaeid Galba cousini and Galba schirazensis and found high infection rates of F. hepatica in G. cousini, but these differed according to the method used, with PCR showing a higher rate (61 ± 20%) compared to rediae observation (29 ± 17%). F. hepatica in G. schirazensis was identified only by DNA amplification. G. cousini populations were genetically structured by geographic distance whereas G. schirazensis populations showed very low genetic diversity. The higher abundance and infection rate of G. cousini compared to G. schirazensis suggests that the former is likely the specie responsible for F. hepatica transmission in this region.

Epidemiological analysis of the New World screwworm (Cochliomyia hominivorax) in Ecuador.

The New World screwworm (Cochliomyia hominivorax) is an obligate parasite that affects warm-blooded animals. It causes myiasis in livestock and humans, which is a problem for animal production and public health. The health and economic burden of myiasis on livestock production is largely unknown in Ecuador. We investigated the presence of the screwworm and analysed the epidemiology and spatial and temporal trends of myiasis in cattle farms of San Miguel de Los Bancos county. In total, epidemiological questionnaires were conducted in 110 farms, which were subsequently monitored for 12 months. The findings show that the initial and final prevalences in farms were 70% and 61.81%, respectively, and the average monthly prevalence was 15.08%. The initial and final prevalences in animals were 3.87% and 4.60% for bovines and 2.91% and 3.36% for all animals examined. The average percentage of new cases reported per month was 17.68% with a minimum of 10 and a maximum of 28 cases in October and May 2015, respectively. The cumulative incidence estimated that the risk for non-infested farms to become infested could reach 100% in approximately 6 months. The incidence rate is 168 per 1,000 farms at risk-monthly. The annual incidence was 459 per 10,000 for bovines at risk-annually. An analysis of hotspots based on the Getis-Ord Gi* index revealed no temporally stable hot spot, but one temporally stable cold spot, suggesting that most of the study area is generally favourable to infestation, except one cluster of farms.

Oestrus ovis in Ecuador: Importance in the Andean sheep farming.

AIM: This study aimed to determine the prevalence of Oestrus ovis in sheep meant for meat commercialization in the main slaughterhouse of the country. MATERIALS AND METHODS: Between October 2015 and December 2015, we assessed the occurrence of Oestrus myiasis in the main slaughterhouse localized in Quito. In total, 80 sheep heads were randomly inspected and necropsied. Larvae were removed from nasal cavities and paranasal sinuses and cleaned. ANOVA (generalized linear model) was used to estimate the relationship between sex, age, and place of origin and presence or absence of parasite larvae. RESULTS: Morphological identification confirmed that 19% (15/80) of the examined animals were positive for Oestrus ovis; from the positive cases, 21% were young animals <12 months old. We found that statistical differences by animal sex, males, were most infested 93% (14/15) than females 7% (1/15). Larvae's L2 were more abundant than other stages (62 of the total 149). 14 of the infested animals were from the Andean places at > 2500 meters above sea level (m.a.s.l.), and only one case from the coastal region at 250 m.a.s.l. with tropical environmental conditions. CONCLUSIONS: Our results showed evidence of the presence of myiasis caused by O. ovis in Andean and coastal places in Ecuador and its adaptation to different environmental conditions from that reported previously in temperate regions from Europe and Africa.

Comparison of complementary diagnostic tests in cerebrospinal fluid and serum for neurocysticercosis.

The role of immunologic tests in the diagnosis of neurocysticercosis (NC) is controversial and few studies have made comparisons among them. The objective of this study was to compare immunological tests in both serum and cerebrospinal fluid (CSF) for the diagnosis of NC. We conducted a case-control study in Cuenca, Ecuador, enrolling patients with NC (N = 24) and matching them with other neurosurgical patients (N = 18). To detect cysticercal antigen, we used an HP10 antigen assay in serum and CSF ("HP10 Ag -serum -CSF") and a commercial antigen assay in serum (apDia, "ELISA-Ag-serum"), and to detect cysticercal DNA, we used a polymerase chain reaction (PCR) assay in CSF ("PCR-CSF"). Assay sensitivities were: HP10 Ag-serum (41.7%, 95% confidence interval [CI] 22.1-63.4), HP10 Ag-CSF (87.5%, 95% CI: 67.6-97.3), ELISA-Ag-serum (62.5%, 95% CI: 40.6-81.2), and PCR-CSF (79.2%, 95% CI: 57.9-92.9). Sensitivities were higher when limiting to participants with extraparenchymal NC. Specificity was 100% for all assays except ELISA-Ag-serum (72.2%). This preliminary study demonstrated the potential usefulness of the PCR and HP10 Ag assay in CSF, especially for extraparenchymal NC; thus, they could be considered as complementary diagnostic tools when neuroimaging is not conclusive.

A new multiplex PCR assay to distinguish among three cryptic Galba species, intermediate hosts of Fasciola hepatica.

A molecular tool described here allows in one step for specific discrimination among three cryptic freshwater snail species (genus Galba) involved in fasciolosis transmission, a worldwide infectious disease of humans and livestock. The multiplex PCR approach taken targets for each species a distinctive, known microsatellite locus which is amplified using specific primers designed to generate an amplicon of a distinctive size that can be readily separated from the amplicons of the other two species on an agarose gel. In this way, the three Galba species (G. cubensis, G. schirazensis, and G. truncatula) can be differentiated from one another, including even if DNA from all three were present in the same reaction. The accuracy of this new molecular tool was tested and validated by comparing multiplex PCR results with species identification based on sequences at mitochondrial and nuclear markers. This new method is accurate, inexpensive, simple, rapid, and can be adapted to handle large sample sizes. It will be helpful for monitoring invasion of Galba species and for developing strategies to limit the snail species involved in the emergence or re-emergence of fasciolosis.

Validation of meat inspection results for Taenia saginata cysticercosis by PCR-restriction fragment length polymorphism.

Bovine cysticercosis is a zoonosis caused by the larval stage (cysticercus) of the human tapeworm Taenia saginata. Infected cattle is an important food safety issue besides an economic concern. Humans get infected by eating raw or undercooked meat containing viable cysticerci. Visual meat inspection of bovines is the only public health measure implemented to control transmission to humans, but it lacks sensitivity and objectivity. It may underestimate the prevalence of the disease by a factor 3 to 10. Furthermore, the success of the method depends on the expertise of the meat inspector as well as on the stage of development of the cysticerci. The focus of this study was to develop and explore the usefulness of a PCR assay as an objective alternative to evaluate the meat inspector's visual inspection results. Hereto, a PCR was developed for the detection of T. saginata DNA in muscle lesions. Based on the laboratory classification of lesions, almost 97% of viable cysts were confirmed by PCR, while for dead cysts, the percentage was approximately 73%. Taken together, these data demonstrate the difficulties of visual meat inspection and their objective interpretation, emphasizing the need to improve current assays to strengthen the control of bovine cysticercosis.

The current status of resistance to alpha-cypermethrin, ivermectin, and amitraz of the cattle tick (Rhipicephalus microplus) in Ecuador.

Rhipicephalus microplus is widely distributed in tropical and subtropical areas of the world where livestock is a principal activity with great veterinary and economic importance. In Ecuador, this hematophagous ectoparasite has been observed between 0 and 2600 masl. One of the main tick control measures is the use of acaricides, which have been indiscriminately used worldwide and in Ecuador. In this country, no studies on acaricide resistance in Rhipicephalus microplus have been published. The current study aims to characterise the level of resistance of R. microplus against three main acaricides commonly used in Ecuador i.e. amitraz, alpha-cypermethrin and ivermectin to determine the level and pattern of dose-responses for R. microplus in 12 field populations (farms). The level of acaricide resistance was evaluated using three different bioassays: adult immersion test (AIT), larval package test (LPT) and larval immersion test (LIT), as recommended by the FAO. The predictive dose-responses were analysed by binomial logistics regression of the larval survival rate (resistance). In general, we found resistance of 67% for amitraz; 50% for alpha-cypermethrin and from 25 to 42% for ivermectin in the twelve field populations analysed. Resistance levels were studied in larval and adult bioassays, respectively, which were slightly modified for this study. For larval bioassays based on corrected mortality i.e. high (above 51%), medium (21-50%) and low (11-20%) resistance, percentages less than 10% were considered as susceptible. For the adult test, two resistance levels were used i.e. high (more than 76%) and medium (51 to 75%) resistance. Percentages lower than 50% were considered as susceptible. In this context, for larval bioassays, amitraz showed 21%, 38% and 8% for high, medium and low resistance, respectively. Alpha-cypermethrin presented 8%, 4 and 38% for high, medium and low resistance, respectively. Ivermectin presented 8%, 25% and 8% for high, medium and low resistance, respectively. For adult tests with amitraz 50% and 17% of the field populations showed average and high resistance, with evidences of average resistance to alpha-cypermethrin in 50% of the samples and average resistance against ivermectin in 25% of the farms. No statistical difference amongst the three bioassays was found and acaricide resistance was confirmed by logistic regression analysis; hence resistance (dose-responses) in each field populations differed, depending on the choice of the acaricide, frequent usage, frequency of treatment and farm management. The effective estimated dose needed to eliminate 99% of ticks is higher than dose recommended by the manufacturer. In conclusion, amitraz showed the highest resistance followed by ivermectin and alpha-cypermethrin and reveals differences on resistance in each individual field population. This information is important in order to establish the monitoring of resistance on each farm individually, contributing to the rational use of acaricides included in an integrated control program for R. microplus.