Incidence of opioid-induced esophageal dysfunction / Incidencia de disfunción esofágica inducida por opiáceos

Background: Retrospective studies have suggested that long-term use of opioids can cause esophageal motility dysfunction. A recent clinical entity known as opioid-induced esophageal dysfunction (OIED) has been postulated. There is no data from prospective studies assessing the incidence of opioid-induced effects on the esophagus. Aim: Evaluate the incidence of OIED during chronic opioid therapy. Methods: From February 2017 to August 2018, all patients seen in the Pain Unit of the hospital, who started opioid treatment for chronic non-neoplastic pain and who did not present esophageal symptoms previously, were included. The presence of esophageal symptoms was assessed using the Eckardt score after 3 months and 1 year since the start of the study. In February 2021, the clinical records of all included patients were reviewed to assess whether esophageal symptoms were present and whether opioid therapy was continued. In patients presenting with esophageal symptoms, an endoscopy was performed and, if normal, a high-resolution esophageal manometry was performed. For a confidence level of 95%, a 4% margin of error and an estimated prevalence of 4%, a sample size of 92 patients was calculated. Results: 100 patients were included and followed while taking opioids, for a median of 31 months with a range between 4 and 48 months. Three women presented with dysphagia during the first 3 months of treatment, being diagnosed with esophagogastric junction outflow obstruction; type II and type III achalasia. The cumulative incidence of OIED was 3%; 95%-CI: 0–6%. Conclusions: Chronic opioid therapy in patients with chronic non-neoplastic pain is associated with symptomatic esophageal dysfunction.(AU)

Antecedentes: Estudios retrospectivos han sugerido que el uso crónico de opiáceos puede causar disfunción esofágica. Se ha postulado una entidad clínica reciente denominada disfunción esofágica inducida por opioides (DEIO). No existen estudios prospectivos que evalúen la incidencia de esta entidad. Objetivo: Evaluar la incidencia de DEIO durante el tratamiento crónico con opiáceos. Métodos: Desde febrero de 2017 hasta agosto de 2018, se incluyeron todos los pacientes atendidos en la Unidad del Dolor de nuestro hospital, que iniciaron opiáceos por dolor crónico no neoplásico sin síntomas esofágicos previos. La clínica esofágica se valoró mediante la escala de Eckardt a los tres meses y al año. En febrero de 2021, se revisaron las historias clínicas de todos los pacientes para evaluar la presencia de clínica esofágica y si continuaban con opiáceos. En los pacientes con síntomas esofágicos, se realizó una gastroscopia y, si era normal, una manometría esofágica de alta resolución. Para un nivel de confianza del 95%, una precisión del 4% y una prevalencia estimada del 4%, se calculó un tamaño muestral de 92 pacientes. Resultados: Se incluyeron 100 pacientes que fueron seguidos mientras tomaban opiáceos, con una mediana de 31 meses y un rango entre 4 y 48 meses. Tres mujeres presentaron un trastorno motor esofágico durante el seguimiento (obstrucción funcional de la unión esofagogástrica; acalasia tipo II y tipo III). La incidencia acumulada fue del 3%; IC 95%: 0-6%. Conclusiones: El tratamiento crónico con opiáceos en pacientes con dolor crónico no neoplásico se asocia a disfunción esofágica sintomática.(AU)

Incidence of opioid-induced esophageal dysfunction.

BACKGROUND: Retrospective studies have suggested that long-term use of opioids can cause esophageal motility dysfunction. A recent clinical entity known as opioid-induced esophageal dysfunction (OIED) has been postulated. There is no data from prospective studies assessing the incidence of opioid-induced effects on the esophagus. AIM: Evaluate the incidence of OIED during chronic opioid therapy. METHODS: From February 2017 to August 2018, all patients seen in the Pain Unit of the hospital, who started opioid treatment for chronic non-neoplastic pain and who did not present esophageal symptoms previously, were included. The presence of esophageal symptoms was assessed using the Eckardt score after 3 months and 1 year since the start of the study. In February 2021, the clinical records of all included patients were reviewed to assess whether esophageal symptoms were present and whether opioid therapy was continued. In patients presenting with esophageal symptoms, an endoscopy was performed and, if normal, a high-resolution esophageal manometry was performed. For a confidence level of 95%, a 4% margin of error and an estimated prevalence of 4%, a sample size of 92 patients was calculated. RESULTS: 100 patients were included and followed while taking opioids, for a median of 31 months with a range between 4 and 48 months. Three women presented with dysphagia during the first 3 months of treatment, being diagnosed with esophagogastric junction outflow obstruction; type II and type III achalasia. The cumulative incidence of OIED was 3%; 95%-CI: 0-6%. CONCLUSIONS: Chronic opioid therapy in patients with chronic non-neoplastic pain is associated with symptomatic esophageal dysfunction.

Burrow builders as ecosystem engineers for pit-building antlions (Neuroptera: Myrmeleontidae).

Burrow builders are often classified as ecosystem engineers because their digging activities regulate the availability of resources for other organisms. As antlion larvae prefer to construct their traps in bare sandy or loose soil, they could benefit from burrowing activities. We investigated the role of burrow builders as ecosystem engineers for antlions (Myrmeleontidae) in a tropical semideciduous forest in Mexico. The number of traps of antlion larvae was recorded on 30 sampling quadrats (45 cm) at the entrance of burrows (of unidentified builders) and on 30 paired off-burrow quadrats. Additionally, the percentage of bare soil was estimated for the 60 quadrats sampled. Of the 30 quadrats at the entrance of burrows, a total of 336 traps were recorded, with 21 (70%) of them having at least one trap, while for the 30 off-burrows quadrats, only two (6.6%) of them had traps, just three in total. The percentage of bare soil and the abundance of traps were significantly greater in quadrats at the entrance of burrows compared to quadrats without burrows. The abundance of traps at the entrance of burrows was positively affected by the percentage of bare soil. The few traps in the off-burrows quadrats suggested that, in addition to the limited bare soil, ground compactness probably limits the establishment of antlion larvae. Otherwise, when digging, burrow builders create small patches of bare sandy soils that are used by these insects. We concluded that the ecosystem engineering effect of burrow builders is an important structuring element for antlion populations in the tropical semideciduous forest studied.

Local Climate Conditions Shape the Seasonal Patterns of the Diptera Community in a Tropical Rainforest of the Americas.

Insect life cycles are short-term and therefore sensitive to immediate changes triggered by climate, vegetation structure, or land use management; hence, the insect populations shape the communities and functional relationships in tropical forests. In this study, we hypothesized that seasonal variations of the dipteran families respond in different ways to changes of weather conditions, thereby affecting their population dynamics. In a one-hectare plot, we surveyed the fly community inhabiting the understory of a Neotropical rainforest. Over a yearly cycle, we used three Malaise traps operated continuously for 365 days and recorded a total of 68,465 fly specimens belonging to 48 families of Diptera, 15 of which were most abundant, accounting for 99.2% of all sampled individuals. The results of the trapping frequency indices (TFIs) exhibited significant population fluctuations in 12 of the 15 most abundant families, which were particularly correlated with temperature or precipitation. Based on such variations, we identified four seasonal patterns as follows: (i) Spring-Autumn bimodal pattern (Cecidomyiidae, Sciaridae, Phoridae, Stratiomyidae); (ii) Spring pattern (Mycetophilidae, Dolichopodidae, Ceratopogonidae); (iii) Autumn pattern (Chironomidae, Psychodidae); (iv) Winter pattern (Empididae, Tipulidae, Ditomyiidae). From a functional perspective, we found the prevalence of families with saprophagous larvae, in addition to phytophagous, fungivores, and predacious. Our results suggest a key role played by the Diptera community on structuring the functional clusters, both in terms of taxonomic composition and on seasonal shifts of abundance, thus influencing the dynamic processes of nutrient cycling in the understory.

A new species of picture-winged flies of the genus Euphara Loew (Diptera, Ulidiidae).

Based on a large series of specimens found in several localities in Mexico Euphara loculata n. sp. is described. It is the second species of this Neotropical genus, and includes for the first time a description and illustration of the male and female genitalia of the genus.

Ecosystem engineering by leaf-rolling mites enhances arthropod diversity.

Many arthropods modify parts of plants through the construction of domiciles or by consuming plant tissues that, after abandoned, can be used as shelter by other arthropods in a facilitating interaction process. We examined, for the first time, the potential of leaf-rolling mites to indirectly influence arthropod communities in natural forests by providing shelter sites. In early June 2019, we found a high density of leaves of Amphitecna tuxtlensis (Bignoniaceae) rolled by an undetermined leaf-rolling mite species in a tropical rainforest, in Mexico. We tested whether the species richness, abundance, and colonization frequency of arthropods was greater in rolled compared with expanded leaves. We collected 5 rolled leaves and 5 fully expanded leaves from 15 A. tuxtlensis trees (N = 150 sampled leaves) and recorded all arthropods on each leaf. We recorded 1421 arthropods from 67 unique morphospecies. We found 39 individuals from 23 morphospecies of arthropods in expanded leaves, and 1382 individuals from 56 morphospecies in rolled leaves. Ants were the most abundant and frequent group and utilized the rolled leaves mainly as nesting sites; 1260 ant individuals were found in 30 nests from three species. Arthropod species richness, abundance, and colonization frequency were greater in rolled leaves compared with expanded leaves. We concluded that the ecosystem engineering effect of leaf-rolling mites may be an important structuring element for arthropod communities on plants through an increase of high quality food resources and shelter sites for other arthropods, as well as nesting sites for ants.

The Mayan Tropical Rainforest: An Uncharted Reservoir of Tritrophic Host-Fruit Fly-Parasitoid Interactions.

Over a two-year period, we surveyed natural areas of the Mayan rainforest in Quintana Roo, Mexico. We found 11 species of Anastrepha Schiner (Diptera: Tephritidae) infesting 25 species of fruits belonging to ten plant families. We report the first records of 10 host plant species of the genus Anastrepha, which include the first report of a plant family (Putranjivaceae) serving as host of Anastrepha fraterculus (Wiedemann) infesting Drypetes lateriflora (Sw.) Krug and Urb. (Putranjivaceae). Pouteria reticulata (Engl.) Eyma (Sapotaceae) was found, for the first time, to be infested by Anastrepha serpentina (Wiedemann) and by a new undescribed species of Anastrepha. We also report Casimiroa microcarpa Lundell (Rutaceae) as a possible ancestral host for the Mexican fruit fly, Anastrepha ludens (Loew), in Central America. The family Sapotaceae was the best-represented host group with three fruit fly species recovered: A. serpentina, an economically-important species, found in eight host plants, and A. hamata and A. sp. (new species). We recorded six species of koinobiont parasitoids: Doryctobracon areolatus Szepligeti, Utetes (Bracanastrepha) anastrephae Viereck, Opius hirtus Fisher, and Doryctobracon zeteki Musebeck, (all Braconidae), and Aganaspis pelleranoi (Brethés) and Odontosema anastrephae Borgmeier, (both Figitidae). All these parasitoid species represent at least a new report for their host plants. Of the whole parasitoid community, D. areolatus was the most important parasitoid species with 52.7% of presence in 12 host plant species, parasitizing six fruit fly species. The interaction between fruit flies and their parasitoids with host plants depends on fruit availability, which is crucial for the survival of each of these species. Conserving the landscape of the Mayan rainforest is important not only for species conservation, but also for the maintenance of fruit fly host plants in orchard agroecosystems in southeastern Mexico.

Giardia intestinalis and Fructose Malabsorption: A Frequent Association.

Nowadays, scientific studies are emerging on the possible etiological role of intestinal parasites in functional digestive disorders. Our study was carried out with healthy individuals (control group; n = 82) and symptomatic patients with lactose or fructose malabsorption, including positive (malabsorbers; n = 213) and negative (absorbers; n = 56) breath test, being analyzed for the presence of intestinal parasites. A high parasitic prevalence was observed in malabsorbers (41.8%), exclusively due to single-cell eukaryotes but not helminths. Giardia intestinalis was the predominant parasite in cases of abnormal absorption (26.5%), significantly associated with fructose malabsorption and doubling the probability of developing this pathology. Within controls, Blastocystis sp. (13.4%) was almost the only parasite, being the second among patients (12.6%), and Cryptosporidium parvum, the last species of clinical relevance, was detected exclusively in two malabsorbers (0.9%). The consumption of ecological food and professions with direct contact with humans arose as risk factors of parasitism. A diagnosis of carbohydrate malabsorption in adulthood is the starting point, making the search for the primary cause necessary. Accurate parasitological diagnosis should be considered another tool in the clinical routine for patients with recurrent symptoms, since their condition may be reversible with adequate therapeutic intervention.

What Can Integrated Analysis of Morphological and Genetic Data Still Reveal about the Anastrepha fraterculus (Diptera: Tephritidae) Cryptic Species Complex?

The South American fruit fly Anastrepha fraterculus (Wiedemann) is a complex of cryptic species, the so-called "Anastrepha fraterculus complex", for which eight morphotypes are currently recognized. A previous analysis of ITS1 in samples of the Anastrepha fraterculus complex, while revealing high distinctiveness among samples from different localities of South America, Central America, and Mexico, no direct association was made between sequence type and morphotype. In the present report, a correlated analysis of morphometry and ITS1 data involved individuals belonging to the same population samples. Although showing a low level of intra-populational nucleotide variability, the ITS1 analysis indicated numerous inter-population sequence type variants. Morphotypes identified by morphometric analysis based on female wing shape were highly concordant with ITS1 genetic data. The correlation of genetic divergence and morphological differences among the tested samples gives strong evidence of a robust dataset, thereby indicating the existence of various taxonomic species within the A. fraterculus complex. However, the data revealed genetic and morphological variations in some regions, suggesting that further analysis is still required for some geographic regions.

Vertical and Horizontal Trophic Networks in the Aroid-Infesting Insect Community of Los Tuxtlas Biosphere Reserve, Mexico.

Insect-aroid interaction studies have focused largely on pollination systems; however, few report trophic interactions with other herbivores. This study features the endophagous insect community in reproductive aroid structures of a tropical rainforest of Mexico, and the shifting that occurs along an altitudinal gradient and among different hosts. In three sites of the Los Tuxtlas Biosphere Reserve in Mexico, we surveyed eight aroid species over a yearly cycle. The insects found were reared in the laboratory, quantified and identified. Data were analyzed through species interaction networks. We recorded 34 endophagous species from 21 families belonging to four insect orders. The community was highly specialized at both network and species levels. Along the altitudinal gradient, there was a reduction in richness and a high turnover of species, while the assemblage among hosts was also highly specific, with different dominant species. Our findings suggest that intrinsic plant factors could influence their occupation, and that the coexistence of distinct insect species in the assemblage could exert a direct or indirect influence on their ability to colonize such resources.

Feeding Specialization of Flies (Diptera: Richardiidae) in Aroid Infructescences (Araceae) of the Neotropics.

Evolution and radiation between insects and flowering plants are both opportunistic and obligatory when the former feeds on the reproductive structures of the latter, whereas direct and indirect effects can influence the fitness of individuals, populations, and plant communities. The Araceae family constitutes an important element of the tropical rainforest of the Neotropics, and its morphology and floral biology provide a remarkable system for studying trophic interactions with insects, including the Richardiidae flies (Diptera). We studied the trophic interactions of the aroid-fly system, assessing infestation rates under natural conditions over an annual cycle. In the Neotropical region, we discovered for the first time that seven aroid species became infested by four richardiid species: Beebeomyia tuxtlaensis Hernández-Ortiz and Aguirre with Dieffenbachia oerstedii Schott and D. wendlandii Schott; B. palposa (Cresson) with Xanthosoma robustum Schott; Beebeomyia sp.3. in association with Philodendron radiatum Schott, P. tripartitum (Jacq.) Schott, and P. sagittifolium Liebm.; while Sepsisoma sp. only infested Rhodospatha wendlandii Schott. Infestation rates differed significantly among hosts, but comparisons with morphological traits did not provide evidence of a causal factor of the infestation. In contrast, larval density and time of development both exhibited significant differences between hosts. The findings suggest the high specialization of the flies, and that intrinsic factors of the plants, such as the presence of secondary metabolites and their maturation periods, may influence their infestation rates.

Blastocystis subtypes and their association with Irritable Bowel Syndrome.

Blastocystis spp. is a common intestinal protozoan that affects humans and animals. The role of this parasite as a pathogen is still controversial and it is suspected to be linked to Irritable Bowel Syndrome (IBS), a functional bowel disorder characterized by chronic or recurrent abdominal pain associated with altered intestinal habits. A broad search in electronic databases, libraries, portals of journals, etc. for reports on the association between the parasite and IBS without language restriction was performed. The selection was not restricted by date, but articles published in the last seven years were given preference. We investigated the evidence regarding Blastocystis and IBS coexistence as well as the implications of the parasite in pathogenesis and clinical manifestations. Only standardized parasitological tools, supplemented by epidemiological analysis, will be able to clarify whether parasite carriage could be connected to IBS and its status as a human pathogen. Although a variation in pathogenicity and virulence between subtypes has been confirmed, Blastocystis can only be considered an indicator of dysbiosis. Accurate diagnoses of this parasitic eukaryote, specifically at genotypic and phenotypic levels, as well as the complete analysis of the intestinal microbial communities, have to be included in the protocol of those patients with IBS.

Obstrucción funcional de la unión esofagogástrica inducida por opiáceos / Opioid-induced functional esophagogastric junction obstruction

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Dyspnea and dysphagia associated to hypopharyngeal fibrolipoma: A case report.

Fibrolipomas are benign lesions conformed by fat and connective tissue, classified as histologic variants of lipomas. They are rarely located in the head and neck and represent less than 0.6% of the benign tumors of the larynx and hypopharynx. Their clinical presentation depends on its location and size. We present the case of a 51-year-old male patient who reported progressive dyspnea, dysphagia and obstructive sleep symptoms with a duration of 3 months, without apparent cause. A pharyngolaryngeal fiberoptic endoscopy showed a smooth, rounded mass in the posterior wall of the hypopharynx, partially obstructing the laryngeal vestibule, creating a valve effect. Complete trans-cervical resection of the lesion was performed after the airway was secured by means of a tracheotomy. The final histopathology report was fibrolipoma. He is currently asymptomatic and without evidence of relapse one year after the procedure.

Decreased Esophageal Sensitivity to Acid in Morbidly Obese Patients: A Cause for Concern?

BACKGROUND/AIMS: To evaluate esophageal sensitivity to acid between morbidly obese (MO) patients and non-MO controls with abnormal esophageal acid exposure. METHODS: We conducted a cross-sectional study of 58 patients: 30 MO (cases) and 28 non-MO (controls). Esophageal symptoms and esophageal sensitivity to 0.1 M hydrochloric acid solution (Bernstein test) were compared between MO and non-MO patients with a prior diagnosis of abnormal esophageal acid exposure. RESULTS: MO patients were less symptomatic than non-MO controls (14% vs 96%; odds ratio [OR], 0.006; 95% confidence interval [CI], 0.001 to 0.075; p=0.000). MO patients were more likely to present with decreased esophageal sensitivity to the instillation of acid than non-MO controls (57% vs 14%; OR, 8; 95% CI, 1.79 to 35.74; p=0.009). Subgroup analysis revealed no differences in esophageal sensitivity in MO patients with and without abnormal esophageal acid exposure (43% vs 31%; p=0.707). CONCLUSIONS: Silent gastroesophageal reflux disease (GERD) is common among MO individuals, likely due to decreased esophageal sensitivity to acid. The absence of typical GERD symptoms in these patients may delay discovery of precancerous conditions, such as Barrett's esophagus. We believe that these patients may require a more aggressive diagnostic work-up to rule out the presence of silent GERD.

Effects of high-resolution esophageal manometry on oxygen saturation and hemodynamic function.

The effect of high-resolution esophageal manometry (HRM) on oxygen saturation (SaO2) and hemodynamic function has not been previously evaluated. This was a prospective study of consecutive patients referred for HRM. Demographic and clinical data were collected on all patients. The study variables included SaO2, heart rate (HR) and blood pressure (BP). SaO2 and HR were measured at baseline, during intubation, during and 5 min after HRM. BP was measured at baseline, during and after HRM. 158 (56% women) patients with a mean age of 56 (SD 15) years were included. Thirty-five (22%) were obese and 55 (35%) were overweight. Eighteen (12%) patients had a history of respiratory disease and 27 (17%) were smokers. Intubation was difficult in 22%. Exploration tolerance was poor in 17% or very poor in 6%. The average duration of the test was 9.9 (SD 2.8) minutes. Sixty-four (47%) and 59 (37%) patients had SaO2 below 95% during intubation and during HRM, respectively. Three patients had SaO2 ≤90%. Sixty-nine (44%) patients had tachycardia during intubation and 8 (5%) during HRM. The appearance of desaturation (SaO2 <95%) during intubation was associated with a lower basal SaO2; desaturation during HRM and 5 minutes after HRM was associated with a higher age, a higher BMI and a lower basal SaO2. HRM decreases SaO2 and increases heart rate primarily during the insertion of the probe, as part of the standard stress response and therefore HMR can be considered a safe procedure. However, in older and overweight patients, respiratory parameters should be monitored.

Wolbachia strains in cryptic species of the Anastrepha fraterculus complex (Diptera, Tephritidae) along the Neotropical Region.

Infection by Wolbachia was described previously in eleven species of Anastrepha fruit flies some of which are important pests of fruticulture. One such species is the nominal Anastrepha fraterculus, the South American fruit fly, which actually comprises a complex of cryptic species. The suggestions of using Wolbachia for the control of these pest species, make imperative a more precise characterization of the existing strains of the bacteria. In this study, population samples of the A. fraterculus complex from Brazil, Argentina, Peru, Ecuador, Colombia, Guatemala and Mexico were analyzed for Wolbachia infection. The bacteria were genotyped by the MLST and WSP Typing methodologies. All samples were infected with Wolbachia of supergroup "A". For each of the five MLST genes, unique as well as already known alleles were detected. Nineteen sequence types for the concatenated sequences of the five MLST genes, and twenty wsp alleles were found in the samples. Host-specific haplotypes, shared strains among distinct hosts, and more than one strain of Wolbachia were found in some population samples. Recombination among the MLST genes and intragenic recombination between wsp haplotypes was rare. Phylogenetic analysis showed a great similarity among the Wolbachia strains in the A. fraterculus complex. However, some strains of Wolbachia are found throughout the Neotropical Region and there are specific strains in determined geographical areas.

[Prevalence of human papillomavirus infection in squamous cell carcinoma of the oral cavity, oropharynx and larynx]. / Prevalencia de infección por virus del papiloma humano en carcinoma espinocelular de cavidad oral, orofaringe y laringe.

BACKGROUND: Cancer of the head and neck comprises a group of neoplasms that share a similar anatomical origin. Most originate from the epithelium of the aerodigestive tract and 90% correspond to squamous cell carcinoma. In the last 15 years, an increase in the incidence of squamous cell carcinoma induced by human papillomavirus (HPV) has been seen, mainly types 16 and 18, which are the most frequent found in cancers of the oral cavity and oropharynx, and types 6 and 11 in laryngeal cancer. There are reports in the literature that show HPV as the leading cause of oropharyngeal squamous cell carcinoma. OBJECTIVE: Determine the prevalence of infection with high-risk HPV in patients diagnosed with squamous cell carcinoma of the oral cavity, oropharynx and larynx. MATERIAL AND METHODS: An observational, cross-sectional, descriptive, unblinded study was performed. Prevalence of HPV infection was determined by polymerase chain reaction (PCR) in DNA samples from tumour tissue of patients with squamous cell carcinoma of the oral cavity, oropharynx and larynx. Typing was subsequently performed in HPV positive samples in order to detect types 18, 16, 11 and 6, using custom primers. RESULTS: A total of 45 patients were included. The association between laryngeal squamous cell carcinoma and HPV was established in two patients, which represented an overall prevalence of 4.4% in our population, and 10% for laringeal tumours. CONCLUSIONS: There is a low prevalence of HPV infection in squamous cell carcinoma of the oral cavity, oropharynx and larynx, in our population. Prospective studies on younger patients could provide more information.

Morphometric study of third-instar larvae from five morphotypes of the Anastrepha fraterculus cryptic species complex (Diptera, Tephritidae).

The occurrence of cryptic species among economically important fruit flies strongly affects the development of management tactics for these pests. Tools for studying cryptic species not only facilitate evolutionary and systematic studies, but they also provide support for fruit fly management and quarantine activities. Previous studies have shown that the South American fruit fly, Anastrepha fraterculus, is a complex of cryptic species, but few studies have been performed on the morphology of its immature stages. An analysis of mandible shape and linear morphometric variability was applied to third-instar larvae of five morphotypes of the Anastrepha fraterculus complex: Mexican, Andean, Ecuadorian, Peruvian and Brazilian-1. Outline geometric morphometry was used to study the mouth hook shape and linear morphometry analysis was performed using 24 linear measurements of the body, cephalopharyngeal skeleton, mouth hook and hypopharyngeal sclerite. Different morphotypes were grouped accurately using canonical discriminant analyses of both the geometric and linear morphometry. The shape of the mandible differed among the morphotypes, and the anterior spiracle length, number of tubules of the anterior spiracle, length and height of the mouth hook and length of the cephalopharyngeal skeleton were the most significant variables in the linear morphometric analysis. Third-instar larvae provide useful characters for studies of cryptic species in the Anastrepha fraterculus complex.