RESUMEN

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) virus is thought to have originated in wild bats from Asia, and as the resulting pandemic continues into its third year, concerns have been raised that the virus will expand its host range and infect North American wildlife species, including bats. Mexican free-tailed bats (Tadarida brasiliensis) live in large colonies in the southern United States, often in urban areas and, as such, could be exposed to the virus from infected humans. We experimentally challenged wild T. brasiliensis with SARS-CoV-2 to determine the susceptibility, reservoir potential, and population impacts of infection in this species. Of 10 bats oronasally inoculated with SARS-CoV-2, 5 became infected and orally excreted moderate amounts of virus for up to 18 days postinoculation. These five subjects all seroconverted and cleared the virus before the end of the study with no obvious clinical signs of disease. We additionally found no evidence of viral transmission to uninoculated subjects. These results indicate that while T. brasiliensis are susceptible to SARS-CoV-2 infection, infection of wild populations of T. brasiliensis would not likely cause mortality. However, the transmission of SARS-CoV-2 from T. brasiliensis to or from humans, or to other animal species, is a possibility requiring further investigation to better define. IMPORTANCE As the COVID-19 pandemic has continued for 3+ years, there has been increasing concern that the SARS-CoV-2 virus will enter wildlife populations and potentially create new reservoirs where the virus could adapt to a new host and create variants. This is particularly possible with species that reside in man-made structures, in proximity to infected human populations. Mexican free-tailed bats (Tadarida brasiliensis) live in large colonies, often in urban settings and, thus, can be exposed by infected humans and potentially transmit the virus to new hosts. We experimentally challenged T. brasiliensis with SARS-CoV-2 and revealed that they are susceptible to the virus and excrete moderate amounts for up to 18 days postinoculation. This is important information for wildlife biologists, wildlife rehabilitation workers, and the general public that may contact these animals.

Asunto(s)

RESUMEN

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) virus originated in wild bats from Asia, and as the resulting pandemic continues into its third year, concerns have been raised that the virus will expand its host range and infect North American wildlife species, including bats. Mexican free-tailed bats ( Tadarida brasiliensis : TABR) live in large colonies in the southern United States, often in urban areas, and as such, could be exposed to the virus from infected humans. We experimentally challenged wild TABR with SARS-CoV-2 to determine the susceptibility, reservoir potential, and population impacts of infection in this species. Of nine bats oronasally inoculated with SARS-CoV-2, five became infected and orally excreted moderate amounts of virus for up to 18 days post inoculation. These five subjects all seroconverted and cleared the virus before the end of the study with no obvious clinical signs of disease. We additionally found no evidence of viral transmission to uninoculated subjects. These results indicate that while TABR are susceptible to SARS-CoV-2 infection, infection of wild populations of TABR would not likely cause mortality. However, the transmission of SARS-CoV-2 from TABR to or from humans, or to other animal species, is a distinct possibility requiring further investigation to better define.

RESUMEN

Genome sequences of three Wheat streak mosaic virus (WSMV) strains were compared. The Type and Sidney 81 strains of WSMV from the American Great Plains were closely related, with sequence identities of 97.6% (nucleotide) and 98.7% (amino acid). In contrast, the El Batán 3 strain from central Mexico was divergent, and shared only 79.2-79.3% (nucleotide) and 90.3-90.5% (amino acid) sequence identity with Type and Sidney 81. All three WSMV strains were serologically related, however the El Batán 3 capsid protein (CP) had 15 fewer amino acid residues. Phylogenetic analysis of the CP cistron indicated that Type, Sidney 81, and nine other American isolates of WSMV were closely related and distinct from the El Batán 3 sequence. Nucleotide substitutions among the WSMV strains were not randomly distributed across the genome with more variation within P1, HC-Pro, and CP, and less within P3. One 400-nucleotide region of the genome, corresponding to the 3'-end of P3, was strikingly deficient in silent substitutions. Nonetheless, the ratio of synonymous to non-synonymous substitutions throughout the genome was essentially the same for all three WSMV strains. Collectively, our data indicate that both genetic drift and negative selection have contributed to the evolution of WSMV strains.

Asunto(s)

RESUMEN

Cross-protection and vector transmission bottlenecks have been proposed as mechanisms facilitating genetic isolation of sympatric viral lineages. Molecular markers were used to monitor establishment and resolution of mixed infections with genetically defined strains of wheat streak mosaic virus (WSMV). Two closely related WSMV strains from the U.S. (Type and Sidney 81) exhibited reciprocal cross-protection in wheat, confirming this classic phenomenon as a mechanism of genetic isolation. In contrast, cross-protection between either U.S. strain and the divergent El Batán 3 strain from Mexico was unilateral, erratic, and only partially effective. Distribution of WSMV strains within individual leaves of plants supporting a mixed infection of Type and Sidney 81 was spatially nonuniform. Strain distribution among individual tillers of coinfected plants also was heterogeneous, with some containing either Type or Sidney 81 alone and some containing both. Transmission by wheat curl mites, acquiring virus from source plants simultaneously infected with both Type and Sidney 81, often resulted in test plants bearing only a single WSMV strain. Spatial subdivision of virus strains within coinfected plants likely contributed to vector transmission bottlenecks during acquisition. Collectively, these three distinct mechanisms enhance genetic isolation of individual viral lineages, and together with stochastic processes, may explain generation and maintenance of genetic diversity in field populations.

Asunto(s)

RESUMEN

Birth weight is related to neonatal health and long-term risk of chronic disease. Since animal studies have shown that birth outcome is related to placental function, the present project was designed to explore the relationship between birth weight and placental growth and composition with maternal factors during pregnancy among normal term pregnancies in 51 primiparous and 40 multiparous women delivering at the University Hospital of the West Indies. Both groups were followed from 15 weeks of gestation to term. The primiparous group was generally younger than the multiparous (mean age 22 +/- 4 versus 31 +/- 5 yr). They were significantly lighter (55 +/- 8 versus 61 +/- 9 kg) with a lower body mass index (21 +/- 3 versus 23 +/- 4 kg/m2) during early pregnancy, but gained more weight during pregnancy, 11 kg compared with 8 kg, respectively. The duration of pregnancy was similar for both groups. Although the size of the placenta was not significantly different between the two groups, the mean weight of the multiparous placentae was more than that of the primiparous placentae. Also, for all mothers both placental weight and initial maternal weight related directly to birth weight. Placental non collagen protein (NCP), sodium and potassium contents were significantly higher for multiparous women and were related to birth weight. The primiparous group had babies who were significantly lighter, 3.03 kg compared with 3.36 kg, for the multiparous and this could be attributed to differences in placental function and maternal weight. When account was taken of the difference in maternal weight at the start of pregnancy and the difference in placental weight, parity no longer explained any of the differences in birth weight. It is concluded that maternal body weight at the time of becoming pregnant and the early development of the placenta determine the efficiency with which nutrients might be delivered to the foetus and hence foetal growth. The difference in birth weight between primiparous and multiparous women can be explained by the differences in maternal weight at the time of becoming pregnant.

Asunto(s)

RESUMEN

Glanzmann's thrombasthenia is a rare congenital disorder of platelet function manifesting as defective primary haemostasis. Bleeding episodes often require platelet transfusions, and allo-immunization to donor platelets may occur. The problems of ensuring adequate haemostatic potential for delivery of an allo-immunized pregnant female with Glanzmann's thrombasthenia are presented.

Asunto(s)

RESUMEN

During a study of nutrition in pregnancy, the diets of 108 Jamaican pregnant women were assessed by single 24-hour recalls. The women were 16-45 years old, of mixed parity (0-9), attended private (23 per cent) and public (77 per cent) antenatal clinics and differed in stage of pregnancy at interview. Mean energy intake (2110 +/- 739 kcal/d) was low, 83 per cent of the average Recommended Dietary Allowance for the Caribbean (CFNI 1976). Most (76 per cent) women had low energy and dietary iron (75 per cent) intakes. Fewer women had low riboflavin (42 per cent) or protein intakes (29 per cent). Maternal age, parity, obstetric performance, and unusual cravings influenced maternal nutrition to some extent. Dietary assessments overestimated the risk of maternal malnutrition.

Asunto(s)

RESUMEN

Pregnancy in chronic active hepatitis and cirrhosis is rare. There is an appreciable perinatal mortality and the effect of pregnancy on the underlying liver disease remains uncertain. Two patients with autoimmune chronic active hepatitis with cirrhosis who became pregnant during an active stage of their disease while on therapy are described. Both had an uneventful pregnancy with successful deliveries. One of the patients had two other pregnancies but the pregnancy had to be terminated because of clinical deterioration. With close supervision patients with chronic active hepatitis and cirrhosis may have successful pregnancies.

Asunto(s)

Asunto(s)

RESUMEN

A cross-sectional study was carried out among 18 Jamaican pregnant women divided into three groups of 6 subjects according to the stage of pregnancy: group B, 12 weeks, group C, 24 weeks and group D, 33 weeks. A group (group A) of 6 non-pregnant women was selected as control. The rate of whole-body protein turnover was measured by continuous oral administration of 15N-glycine and the resting metabolic rate by the open-circuit method. All subjects had a normal pregnancy outcome. The composition of the diet on the day of the study was comparable between the four groups (approximately 80 g protein and 9.45 MJ energy) and not significantly different from the composition of the diet during the 2 d prior to the experiment. The rates of protein synthesis and breakdown were higher in groups B and C compared to group A and lower in group D where they reached values slightly higher than in group A. Estimated from urea enrichment, these rates did not vary significantly among the groups, while estimated from ammonia enrichment the difference was significant (P less than 0.05) and there was a negative correlation between the gestational age and the rate of synthesis (r = -0.63) and breakdown (r = -0.69). Nitrogen retention was comparable between the three groups of pregnant women and significantly higher than in the group A. The resting metabolic rate was similar between the groups of pregnant women. These results suggest that the rates of protein turnover observed during gestation reflect more the changes that occur in maternal than those in fetal tissues. The values for protein synthesis and nitrogen retention indicate that the amount of protein deposited during pregnancy is greater than that expected on the basis of body composition analysis. It is also suggested that as pregnancy proceeds whole-body protein turnover represents a smaller part of the resting metabolic rate.

Asunto(s)

Asunto(s)

Asunto(s)

Asunto(s)

Asunto(s)

Asunto(s)

Asunto(s)

Asunto(s)

Asunto(s)

Asunto(s)

Asunto(s)