Insectos asociados a productos alimenticios almacenados en el área urbana de Culiacán, Sinaloa, México / Insects associated with food products stored in the urban area of Culiacán Sinaloa, Mexico

Resumen Los insectos asociados a productos almacenados dañan a una amplia variedad de alimentos en hogares y expendios, provocando baja calidad nutricional e incluso riesgo a la salud de los consumidores. El objetivo de este estudio fue determinar las especies y abundancia de insectos asociados a alimentos secos almacenados en casas y tiendas de abarrotes de la ciudad de Culiacán, Sinaloa. Se obtuvieron productos alimenticios, en casas o tiendas de abarrotes, con indicios de daños por insectos o presencia de los mismos, los cuales fueron trasladados al laboratorio, donde se aislaron los imagos. Los organismos inmaduros y las muestras de alimento seco se depositaron en cámaras de emergencia de adultos debido a que la identificación se llevó a cabo por morfología en la fase de imago. Se recolectaron 181 ejemplares de insectos pertenecientes a 8 especies; de ellas, Oryzaephilus mercator (Fauvel), Necrobia rufipes (De Greer), Plodia interpunctella (Hubner) y Cadra cautella (Walker) son nuevos registros para Sinaloa. En las casas se encontró la mayor cantidad de insectos, principalmente del orden coleoptera (U = 96.000, n = 154, P = 0.004). Las especies N. rufipes, T. castaneum (Herbst) y P. interpunctella fueron las más comunes en los sitios de estudio y en las muestras recolectadas. Por primera vez se caracterizó y se determinó la abundancia de insectos plaga de productos alimenticios almacenados en una zona urbana de Sinaloa, entidad federativa con importancia agraria en México. Ubicar taxonómicamente las especies que infestan productos almacenados ayuda a determinar el riesgo económico y de salud que representan para las zonas donde fueron encontrados. También es útil para desarrollar y aplicar medidas adecuadas de control entomológico, en caso de presentarse una plaga en la zona, lo que mantendrá la calidad e integridad de los productos que se comercializan.

Abstract Insects associated with stored produce damage a wide variety of foods in homes and grocery stores, causing poor nutritional quality and even health risk in consumers. The objective of this study was to determine the species and abundance of insects associated with dry food products stored in homes and grocery stores of the city of Culiacán, Sinaloa. Food products were obtained, in houses or grocery stores, with signs of damage by insectes or their presence, which were transferred to the laboratory, where the imagos were isolated immature and dry food samples were deposited in adult emergency chambers because the identification was carried out by morphology in the imago stage. 181 insects belonging to 8 species were collected, of which Oryzaephilus mercator (Fauvel), Necrobia rufipes (De Greer), Plodia interpunctella (Hubner) and Cadra cautella (Walker) represent new records for the state of Sinaloa. The highest number of insects that belong mainly to the order coleoptera were collected in homes (U = 96.000, n = 154, P = 0.004). N. rufipes, T. castaneum (Herbst) and P. interpunctella were the most common species at the study sites and of the food samples collected, dog food and flour were the most affected. For the first time, the abundance of insect pests of stored food products was characterized and determined in an urban area of Sinaloa, an agriculturally important state in Mexico. Identifying taxonomically the species that infest stored products will allow to determine the economic and health risk that they represent for the areas where they were found. It is also useful in developing and applying the appropriate entomological control that will maintain the quality and integrity of the products.

Molecular Detection of Leishmania (L.) mexicana (Kinetoplastida: Trypanostomatidae) DNA in Culicoides furens (Diptera: Ceratopogonidae) from an Area with Autochthonous Canine Leishmaniasis in Northwestern Mexico.

PURPOSE: Mexico is considered endemic for Leishmania; recent reports indicate autochthonous human and canine leishmaniasis caused by Leishmania mexicana in Sinaloa state. Lutzomyia sand fly are the primary vector of the parasite, although no records of phlebotomine vectors of Leishmania exist from Sinaloa. Other hematophagous dipterans, like Culicoides, could represent possible vectors of Leishmania in absence of phlebotomines. The known distribution of Culicoides includes the southern portion of Sinaloa state, in northwestern Mexico, with records of Culicoides furens. However, no studies have demonstrated the presence of Leishmania in C. furens or its possible participation in the parasite's life cycle in Mexico. This study, therefore, sought to detect DNA of Leishmania in C. furens captured in an endemic area of autochthonous canine leishmaniasis in northwestern Mexico. METHODS: Culicoides were captured with CDC light traps, identified morphologically, and organized in pools. DNA was extracted, and used to amplify the ribosomal ITS1 region of Leishmania. PCR products were digested with HaeIII endonuclease; the banding patterns obtained were compared to reference strains. RESULTS: Leishmania mexicana DNA was detected in five out of nine pools (55%) of female C. furens. CONCLUSION: This study offers the first evidence of L. mexicana DNA in C. furens, in an endemic area of canine leishmaniasis in northwestern Mexico, where no evidence exists of the presence of phlebotomine sand fly.

First report of autochthonous canine leishmaniasis caused by Leishmania (L.) mexicana in Sinaloa, Mexico.

Leishmaniasis is a neglected tropical disease caused by different species of protozoan parasites of the genus Leishmania. Dogs have been proven as primary hosts of the parasite. Cases of cutaneous leishmaniasis in humans caused by Leishmania mexicana have been reported in Sinaloa; however, the vectors and hosts involved in the epidemiology of the parasite in northwestern Mexico are still unknown. Given the public health implications of this parasite's domestic hosts regarding the permanence and transmission of the disease to humans, the objective of the present study was to detect and determine the species of Leishmania that caused the first three cases of autochthonous canine leishmaniasis in the state of Sinaloa, Mexico. Three domestic dogs showing symptoms similar to canine leishmaniasis were identified, including chronic eye inflammation, corneal opacity, ocular exudate, emaciation and hyporexia. DNA was extracted from venous blood of the infected animals using a commercial kit. The internal transcribed spacer (ITS-1) of ribosomal DNA (rDNA) was amplified by specific primers for Leishmania from the extracted DNA, and the PCR products were digested with the restriction enzyme HaeIII. In addition, PCR products were subjected to automated sequencing. Molecular analysis showed that the infecting species was L. mexicana. This is the first report of autochthonous canine leishmaniasis caused by L. mexicana in Sinaloa, Mexico. Further studies are required to identify the species that serve as vectors and other wild and domestic hosts of the parasite, as well as to determine if there are more species of Leishmania circulating in Sinaloa.

High frequency of HPV16 European variant E350G among Mexican women from Sinaloa.

BACKGROUND & OBJECTIVES: Human papillomavirus (HPV) infections play a crucial role in the aetiology of cervical cancer (CC), and HPV16 is the primary viral genotype associated with CC. A number of variants of the HPV16 E6 gene are involved in the progression of CC, differing in their prevalence and biological and biochemical properties. This study was designed to determine the frequency of HPV types 16/18 and to identify the presence of HPV16 E6-variants in asymptomatic Mexican women. METHODS: A total of 189 cervical Pap smears were collected from women attending public health services in three different cities in Sinaloa, Mexico. Viral DNA was identified by amplification of E6 viral gene fragments using polymerase chain reaction (PCR). Identification of variants was done by sequencing a DNA fragment (321bp) of the HPV16 E6 gene. RESULTS: More than half of the women tested were HPV-positive (52.38%), with HPV16 being the most frequent genotype (21.16%), followed by HPV18 (8.99%). Sequence analysis of the E6-HPV16 PCR products showed that in all cases, the viruses corresponded to European variants. It was further observed that the E350G intra-variant was the most common (>76%). INTERPRETATION & CONCLUSIONS: This study showed a predominance of European lineage variants of HPV16 among asymptomatic women from Sinaloa, Mexico, predominantly with of the E350G variant. This variant has been shown to be associated with an increased risk of early development of CC. The use of molecular identification of carcinogenic HPV and Pap test screening may be a good strategy for monitoring women to prevent CC.

First Evidence of Vertical Infection of Dengue Virus 2 in Aedes aegypti Mosquitoes from Sinaloa, Mexico.

Fourteen pools of Aedes aegypti larvae collected within the urban area of Culiacán, Sinaloa, were analyzed by RT-PCR. The results demonstrate, for the first time, the vertical infection of serotype-2 dengue virus (DENV-2) in Sinaloa, Mexico, suggesting that Ae. aegypti acts as a natural reservoir of DENV-2 in this region.

Is Gnathostoma turgidum an annual parasite of opossums? Drastic seasonal changes of infection in Didelphis virginiana in Mexico.

Gnathostoma turgidum is a nematode that parasitizes the stomach of opossums, Didelphis virginiana. Despite its wide distribution in the Americas, its natural life cycle is poorly understood. Recently, we found an endemic area for G. turgidum infection in Sinaloa, Mexico (Diaz-Camacho et al., 2009). Based on sporadic surveys for several years, the prevalence was apparently high in summer and extremely low in winter. To confirm that this is really a seasonal variance, we conducted a longitudinal survey on G. turgidum infection in opossums from November 2007 to November 2008. The results showed amazing seasonal changes in the prevalence, with synchronized migration and maturation of worms in opossums. Between February and March, many juvenile worms, with occasional AL3, were found in the liver, but no worms were found in the stomach. Mature adult worms began to appear in the stomach around April and rapidly increased in number toward July, when all worms resided in the stomach. Then, the worms disappeared almost completely by November. These results suggest that G. turgidum is an annual parasite of the opossum, D. virginiana, in Mexico.

Acute outbreak of gnathostomiasis in a fishing community in Sinaloa, Mexico.

An increasing number of human cases of gnathostomiasis have been reported in Sinaloa, Mexico, most of whom have a custom of eating of raw fish dishes such as 'cebiche'. Here we report five adult patients, three women and two men, having an acute episode of vomiting and abdominal pain a few minutes after eating a dish of cebiche prepared from a spotted sleeper perch (Eleotris picta) fished from a nearby lake in southern Sinaloa. All five patients experienced acute throat pain, chest and joint pains, headache and fever. One patient, a 55-year-old male, was hospitalized with suspected pancreatitis and pneumonia. By 8-9 days later, all five patients developed between three and 12 edematous, migrating skin lesions on the back, abdomen, upper and lower extremities, face, eye and scalp. By ELISA, all of them were sero-positive to Gnathostoma doloresi antigen and had elevated IgE levels. Eosinophilia was found in two patients. These patients lived in an agricultural and fishing community. In this community we carried out a sero-epidemiological survey and study of living conditions in a random sample of 309 individuals distributed in 74 households. Frequent consumption of raw fish was reported in 36% of households, and 12 individuals had a clinical history of migrating skin lesions. The sero-prevalence to Gnathostoma antigens was 34.95%. Five fish species and four species of ichthyophagous birds collected from three lakes in the village and a nearby estuary were infected with the advanced third-stage larvae of G. binucleatum, a species found in Ecuador and Mexico. The results describe the first known outbreak of acute gnathostomiasis on the American continent.