Morphometric analysis of Triatoma dimidiata populations (Reduviidae:Triatominae) from Mexico and Northern Guatemala.

Triatoma dimidiata is one of the major vectors of Chagas disease in Latin America. Its range includes Mexico, all countries of Central America, Colombia, and Ecuador. In light of recent genetic analysis suggesting that the possible origin of this species is the Yucatan peninsula, we have analyzed populations from the state of Yucatan, San Luis Potosi, and Veracruz in Mexico, and a population from the southern region of the Yucatan peninsula located in Northern Guatemala, the region of El Peten. Classical morphometry including principal component, discriminant, sexual dimorphism, and wing asymmetry was analyzed. San Luis Potosi and Veracruz populations were indistinguishable while clearly separate from Yucatan and Peten populations. Despite important genetic differences, Yucatan and Peten populations were highly similar. Yucatan specimens were the smallest in size, while females were larger than males in all populations. Only head characters were necessary to distinguish population level differences, although wing fluctuating asymmetry was present in all populations. These results are discussed in light of recent findings suggesting genetic polymorphism in most populations of Triatoma dimidiata south of Chiapas to Ecuador.

Morphometric analysis of Triatoma dimidiata populations (Reduviidae: Triatominae) from Mexico and Northern Guatemala

Triatoma dimidiata is one of the major vectors of Chagas disease in Latin America. Its range includes Mexico, all countries of Central America, Colombia, and Ecuador. In light of recent genetic analysis suggesting that the possible origin of this species is the Yucatan peninsula, we have analyzed populations from the state of Yucatan, San Luis Potosi, and Veracruz in Mexico, and a population from the southern region of the Yucatan peninsula located in Northern Guatemala, the region of El Peten. Classical morphometry including principal component, discriminant, sexual dimorphism, and wing asymmetry was analyzed. San Luis Potosi and Veracruz populations were indistinguishable while clearly separate from Yucatan and Peten populations. Despite important genetic differences, Yucatan and Peten populations were highly similar. Yucatan specimens were the smallest in size, while females were larger than males in all populations. Only head characters were necessary to distinguish population level differences, although wing fluctuating asymmetry was present in all populations. These results are discussed in light of recent findings suggesting genetic polymorphism in most populations of Triatoma dimidiata south of Chiapas to Ecuador.

[The stability of the microalbuminuria numbers in relation to their reading time and mode of preservation]. / Estabilidad de las cifras de microalbuminuria en relación con el tiempo de lectura y el modo de conservación.

OBJECTIVE: To evaluate the stability of microalbuminuria figures in urine samples of diabetic patients, in terms of how the samples are kept, and the time between taking and reading. DESIGN: Descriptive, prospective and observational study. SETTING: Primary care. Teaching health centre, Burgos. PATIENTS: 40 type-2 diabetics had their urinary excretion of albumin measured in 91 first-in-the-morning urine samples with Micral Test II reactive strips. INTERVENTIONS: Samples were analysed the day of their collection, then protected from light and kept at +4 degrees C, with further readings at 24, 48 and 72 hours and at 7, 14, 21 and 28 days after collection. MEASUREMENTS AND MAIN RESULTS: 49 (53.84%) of the 91 samples taken did not vary over the 28 days of the study. In the first three days, there were 64 with unvaried measurements (70.2%). Friedman's test showed p = 0.905. > 93% of samples positive at the beginning remained positive all the time; > 83% of samples negative at the beginning remained negative. Concordance observed was > 90%; kappa index > 80%. CONCLUSIONS: Collection of first urine samples in the morning, stored at +4 degrees C in a fridge and protected from light, did not significantly alter the result of the reading for 4 weeks. Such samples are useful in order to aid study of the albumin excretion rate using Micral Test II reactive strips.