Residual insecticidal activity of long-lasting deltamethrin-treated curtains after 1 year of household use for dengue control

OBJECTIVE

To evaluate the residual insecticidal activity of the PermaNet(®) curtains on Aedes aegypti after 1 year of use in Thai households and to assess the influence of sun and dust exposure, washing practices and detergent use.

METHODS

We sampled UV-protected PermaNet(®) curtains made of a long-lasting deltamethrin-[55 mg/m(2)] treated polyester netting, before (10 curtains) and after 8 (10 curtains) and 12 months (66 curtains) of household use in a field site in Chon Buri, Thailand. We assessed the residual insecticidal activity of the curtains by standard WHO bioassay, using a deltamethrin-susceptible insectarium Aedes aegypti strain.

RESULTS

Mosquito mortality was 100% before distribution, 100% at 8 months and 98.2% (95% CI 97.9-98.5) at 12 months of use. Sunlight, hand-washing and detergent use had no effect on the residual insecticidal activity after 12 months. However, the mosquito survival rate increased by a factor of 6.4 (95% CI 3.5-11.8) on machine-washed curtains and by a factor of 2.0 (95% CI 1.4-2.9) on curtains not covered by dust.

CONCLUSION

The residual insecticidal activity of PermaNet® curtains remains high after 12 months use under field conditions.

[Femoral and humeral head osteonecrosis in a patient with hypofibrinolysis and hyperhomocysteinemia. A case report and a review of the literature]

Osteonecrosis is a disease characterized by the death of marrow and bone tissues. All bones may be affected, most commonly those of the hip, knee, shoulder, ankle as well as the small bones of the hands and feet. When the disease involves a weight-bearing joint there is a significant risk that subarticular fracture may develop leading to disabling arthrosis and requiring, therefore, arthroplasty surgery. Osteonecrosis typically affects patients in their third, fourth and fifth decades of life and is associated with many factors including other diseases and co-morbidities. Multifocal osteonecrosis is defined according to the involvement of at least three separated anatomic sites. We describe the case of a young man with osteonecrosis of the shoulder and hip joints which required total arthroplasty. Among biochemical investigations, an increase in the plasminogen activator inhibitor type 1 (PAI-1) levels associated with mild hyperhomocysteinemia was present. Another finding was the HLA B27, without signs of spondyloarthropathies. In patients with osteonecrosis, especially if multifocal, a careful medical history, a complete physical examination and some biochemical investigations, particularly those related to thrombophilia and hypofibrinolysis, should be performed.

Increasing prevalence of non-clade B HIV-1 strains in heterosexual men and women, as monitored by analysis of reverse transcriptase and protease sequences

OBJECTIVE

We evaluated the prevalence of HIV-1 non-clade B over time in a formerly clade B-restricted area. Protease and reverse transcriptase regions of the pol gene were used for phylogenetic and recombination analysis and for clade assignment to HIV-1 A-D, F-H, J, and K strains of the M group.

METHODS

The pol gene of 349 HIV-1 patients belonging to the Italian Cohort Naive for Antiretrovirals (ICONA) were genotypically analyzed to study the prevalence of antiretroviral-associated resistance mutations. All HIV-1 pol sequences and 32 HIV reference strains were analyzed, including the reference strains for the major HIV-1 subtypes. The non-clade B sequences according to the HIV-1 Subtyping Tool program were further studied by a bootscan analysis (SimPlot) to investigate the likelihood of recombination between subtypes.

RESULTS

Phylogenetic analysis detected 19 of 349 (5.4%) non-clade B subtypes. The proportions of patients carrying non-clade B virus before and after 1997 were 1.9% and 8.4%, respectively (p =.008). Among whites, heterosexual infection and female gender were significantly associated with the presence of non-clade B subtypes (p =.001 and.005, respectively). Non-clade B HIV-1 was harbored by 14.5% of the heterosexuals who were found to be HIV-1 positive after 1997, 60% of whom were women. Bootscan analysis identified four strains as F, two as A, one as C, one as G, and 11 (57.9 %) as non-clade B recombinant subtypes.

CONCLUSION

Detection of HIV-1 subtypes and intersubtype recombinants in a previously clade B-homogeneous area indicates that the HIV-1 epidemic is evolving in Italy and that heterosexuals and women are at increased risk of infection with non-clade B HIV-1 subtypes. Sequences inferred from the pol gene yield to establish the subtype of circulating HIV-1 strains. As a consequence, genotyping of pol gene for testing resistance to antiretrovirals warrants concomitant surveillance of non-clade B subtypes.

Sexual behaviour of heterosexual individuals with HIV infection naive for antiretroviral therapy in Italy

BACKGROUND

Specific information about determinants of sexual behaviour of HIV infected heterosexuals, like injecting drug use (IDU), are essential to design interventions aimed at promoting safer sex practices.

METHODS

We analysed data on sexual behaviour collected, between March 1997 and March 1999, through a self administered questionnaire among 1050 IDUs and 642 non-IDU heterosexuals enrolled in a prospective multicentre cohort study on the natural history of HIV infection.

RESULTS

Among non-IDU heterosexuals, more women (48.5%) than men (25.1%) (p<0.001) reported that they were infected by HIV positive regular partners whose HIV status they were not aware of. Among the 1119 heterosexual males, one fifth reported having had more than 25 sexual partners during their lifetime. Condom use in the last sexual intercourse was more common among heterosexual IDUs (64.9%) than among non-IDU heterosexual males (58.3%) (p=0.05). Heterosexual IDU males were more likely (66.7%) than non-IDU heterosexuals (50.6%) to have an HIV negative partner (p<0.001). Of the 573 heterosexual females studied, 10.2% reported having had more than 25 lifetime sex partners. This proportion was higher among heterosexual IDUs (18.8%) than among non-IDU heterosexuals (4.3%) (p<0.001). Nearly 50% of the women in both groups reported having used a condom in the last intercourse. Almost 57% of heterosexual IDUs had a current HIV negative partner, compared with 34.9% non-IDU heterosexuals (p<0.001). In both sexes, the findings from univariate analysis were confirmed by multiple logistic regression analysis.

CONCLUSIONS

This study identified some important differences, in both males and females, in sexual lifestyles according to injecting drug use (for example, in terms of HIV negative partners). This observation indicates the need to tailor HIV prevention messages according to history of injecting drug use.

[Ultrasonic assessment of the capsular-ligamentous structures of the ankle. Normal features]

The study of normal ankles by means of US has enabled the authors to define the articular system so as to obtain a useful reference for the study of pathological ankles. A real-time (Ansaldo AU 530) unit with a 10 MHz sectorial probe was employed together with a Toshiba unit with a 7.5 MHz sectorial probe. In 6 cases, the stretching of the capsuloligamentous system before arthroscopy was examined. The authors' attention focused on 3 major functional anatomic areas: the talofibular ligament area, the calcaneofibular ligament area, and the deltoid ligament area. The comparison of US scans before and after stretching the capsula with a physiological solution allowed the most interesting structures to be recognized and quantified from a US-anatomical point of view. Useful parameters were both the length of the lateral aspect of the ligament (mean difference in length between rest and exercise conditions: 15 mm for the anterior talofibular ligament and 14 mm for calcaneofibular ligament) and the thickness of intra-articular echoes (mean value: 5 mm).

[Acid-base equilibrium changes associated with acute pulmonary edema. Intra-erythrocytic findings and comparison with plasma values]

A study was made of intra-erythrocyte acid-base balance in 7 subjects with metabolic and 3 with mixed acidosis in the course of acute haemodynamic pulmonary oedema. Comparison with plasma values showed that, in metabolic acidosis, the buffers (bicarbonate) are evenly involved in the maintenance of hydrogen ion balance, whereas in mixed forms a greater demand is made on non-bicarbonate bases. Examination of this phenomenon and its quantitative evaluation are geared to intra-erythrocyte determinations of the acid-base balance, particularly to the very important B.E. index.

[Metabolic alkalosis. III. Spontaneous and experimental compensation mechanisms in plasma and erythrocytes]

Plasma and red cell acid-base balance were studied in 13 patients with metabolic alkalosis and 14 healthy subjects following the infusion of bicarbonate. Differences between the plasma and red cell patterns suggested that application of the results of plasma determinations to the body as a whole could be the cause of serious inaccuracies. Since the changes noted occurred in different combinations according to whether alkalinisation was acute or not, it is felt that cell response to a fall in (H+) varies in relation to the time available for compensation.

[Metabolic alkalosis. Relation between bicarbonate load and the behavior of blood lactic acid in the light of the intra-erythrocyte indices of the acid-base balance]

The plasma an intra-erythrocyte acid-base balance in man was studied, along with blood pyruvate and lactate levels, in acute metabolic alkalosis induced by i.v. infusion of bicarbonate. It was found that the red cell offers a satisfactory expression of the phenomena that occur in the intracellular space. The bicarbonate ion has difficulty in crossing the red cell membrane, while the production of lactate is seen as a fundamental compensation mechanism for rapid buffering of the extra base.

[Clinico-statistical studies of the tibial varism frequent among the school population of the Chiavenna valley and its relation to varus arthropathy of the knee in adults]

384 adolescents in Chiavenna schools were examined in a study of the considerable incidence of tibia vara, seen as a first step towards the patterns of varizing arthrosic deformation of the knee in adults of the same zone; at the same time indications on prophylactic-preventive measures in the field of scholastic and sport medicine were given.

[Metabolic alkalosis. Compensation mechanisms in the light of new experimental data]

Changes in arterial blood and erythrocyte acid-base and electrolyte balance in the course of acute alkalinisation caused by bicarbonate loading showed that extracellular alkalosis has no significant effect on the concentration of intraerythrocyte bicarbonate concentration, though a marked increase in pH and electrolyte balance within the red cell is apparent. Erythrocyte alkalinisation may thus be seen as essentially due to the escape of H+ ions, while the entry of Na+ ions is the main device by which the law of electroneutrality is respected. The literature suggests that lactic acid offers a source of H+ ions for destruction of bicarbonate, whereas the diffusion of the ion lactate within the cell is compensated by the release of Cl-. In addition, the data now reported indicate that the red cell is a sufficiently valid model for the study of phenomena occurring within the intracellular compartment when a state of extracellular alkalinisation in created.