Malaria prevention in international travel

For travelers malaria represents the principal infectious risk of severe complications and death. Infection during traveling depends on the geographical area visited, the predominant species of parasite, the frequency of resistance to antimalarial agents, and whether preventive measures have been taken. Until a vaccine has been developed, prevention strategies consist of providing travelers with information, the use of barrier methods against vector bites, the correct use of chemoprophylaxis, and the possibility of self-diagnosis and treatment. The choice of chemoprophylaxis regimen should be individualized since no regimen guarantees 100% protection or is free of adverse effects or contraindications. The most effective drugs are doxycycline, atovaquone-proguanil and mefloquine while those producing severe adverse effects with the least frequency are atovaquone-proguanil and doxycycline.     

Nadolol plus spironolactone in the prophylaxis of first variceal bleed in nonascitic cirrhotic patients: A preliminary study

Treatment with beta-blockers fails to decrease portal pressure in nearly 40% of cirrhotic patients. Recent studies have suggested that treatment with spironolactone reduces pressure and flow in the portal and variceal systems. This trial was designed to assess if nadolol plus spironolactone is more effective than nadolol alone to prevent the first variceal bleeding. One hundred patients with medium and large varices who had never bled and were without ascites were included in a prospective, randomized, multicenter, double-blind, placebo-controlled trial. The patients were randomized into 2 groups: 51 received nadolol plus placebo (N + P) and 49 received nadolol plus spironolactone 100 mg/d (N + S). Hepatic venous pressure gradient (HVPG) and activity of the renin-aldosterone system (plasma renin activity/plasma aldosterone levels) were measured in 24 patients. There were no significant differences in the appearance of variceal bleeding and ascites between groups at a mean follow-up of 22 +/- 16 months. However, analyzing both complications together, the incidence was significantly higher in the N + P group than in the N + S group (39% vs. 20%; P <.04). Clinical ascites was also higher in patients in the N + P group than in the N + S group (21% vs. 6%; P <.04). Significant increases in plasma renin activity and plasma aldosterone levels were only observed in patients in the N + S group (P <.01). The cumulative probabilities of remaining free of bleeding and ascites were similar in both groups after 70 months of follow-up. In conclusion, these results suggest that nadolol plus spironolactone does not increase the efficacy of nadolol alone in the prophylaxis of the first variceal bleeding. However, when bleeding and ascites were considered together, the combined therapy effectively reduced the incidence of both portal-hypertensive complications.     

Standardized emergency management system and response to a smallpox emergency

The smallpox virus is a high-priority, Category-A agent that poses a global, terrorism security risk because it: (1) easily can be disseminated and transmitted from person to person; (2) results in high mortality rates and has the potential for a major public health impact; (3) might cause public panic and social disruption; and (4) requires special action for public health preparedness. In recognition of this risk, the Los Angeles County Department of Health Services (LAC-DHS) developed the Smallpox Preparedness, Response, and Recovery Plan for LAC to prepare for the possibility of an outbreak of smallpox. A unique feature of the LAC-DHS plan is its explicit use of the Standardized Emergency Management System (SEMS) framework for detailing the functions needed to respond to a smallpox emergency. The SEMS includes the Incident Command System (ICS) structure (management, operations, planning/intelligence, logistics, and finance/administration), the mutual-aid system, and the multi/interagency coordination required during a smallpox emergency. Management for incident command includes setting objectives and priorities, information (risk communications), safety, and liaison. Operations includes control and containment of a smallpox outbreak including ring vaccination, mass vaccination, adverse events monitoring and assessment, management of confirmed and suspected smallpox cases, contact tracing, active surveillance teams and enhanced hospital-based surveillance, and decontamination. Planning/intelligence functions include developing the incident action plan, epidemiological investigation and analysis of smallpox cases, and epidemiological assessment of the vaccination coverage status of populations at risk. Logistics functions include receiving, handling, inventorying, and distributing smallpox vaccine and vaccination clinic supplies; personnel; transportation; communications; and health care of personnel. Finally, finance/administration functions include monitoring costs related to the smallpox emergency, procurement, and administrative aspects that are not handled by other functional divisions of incident command systems. The plan was developed and is under frequent review by the LAC-DHS Smallpox Planning Working Group, and is reviewed periodically by the LAC Bioterrorism Advisory Committee, and draws upon the Smallpox Response Plan and Guidelines of the Centers for Disease Control and Prevention (CDC) and recommendations of the Advisory Committee on Immunization Practices (ACIP). The Smallpox Preparedness, Response, and Recovery Plan, with its SEMS framework and ICS structure, now is serving as a model for the development of LAC-DHS plans for responses to other terrorist or natural-outbreak responses.     

Q Fever in returned febrile travelers

Despite the worldwide distribution of Coxiella burnetii , Q fever is not a frequent infection in travelers. This disease should be considered in recent travelers from the tropics with unknown fever, headache, raised liver enzymes, and low platelets. Five cases in western travelers to the tropics returning with fever are presented.     

Non-injection Drug Use and Injection Initiation Assistance among People Who Inject Drugs in Tijuana,Mexico

Although most people who inject drugs (PWID) report receiving assistance during injection initiation events, little research has focused on risk factors among PWID for providing injection initiation assistance. We therefore sought to determine the influence of non-injection drug use among PWID on their risk to initiate others. We used generalized estimating equation (GEE) models on longitudinal data among a prospective cohort of PWID in Tijuana, Mexico (Proyecto El Cuete IV), while controlling for potential confounders. At baseline, 534 participants provided data on injection initiation assistance. Overall, 14% reported ever initiating others, with 4% reporting this behavior recently (i.e., in the past 6 months). In a multivariable GEE model, recent non-injection drug use was independently associated with providing injection initiation assistance (adjusted odds ratio [AOR] = 2.42, 95% confidence interval [CI] = 1.39–4.20). Further, in subanalyses examining specific drug types, recent non-injection use of cocaine (AOR = 9.31, 95% CI = 3.98–21.78), heroin (AOR = 4.00, 95% CI = 1.88–8.54), and methamphetamine (AOR = 2.03, 95% CI = 1.16–3.55) were all significantly associated with reporting providing injection initiation assistance. Our findings may have important implications for the development of interventional approaches to reduce injection initiation and related harms. Further research is needed to validate findings and inform future approaches to preventing entry into drug injecting.     

Evaluation of the genetic variability found in Brazilian commercial vaccines for infectious bronchitis virus

Infectious bronchitis virus (IBV) is currently one of the most important pathogens in the poultry industry. The H120 and Ma5 are the only viral strains approved by the Brazilian government as the constituent of vaccines. Despite the systematic vaccination in Brazil, IBV has not yet been controlled and diseases associated with this virus have been reported in vaccinated chickens. Here, we investigated the genetic variability of H120 and Ma5 strains present in the IBV vaccines from different Brazilian manufacturers. We performed DNA sequencing analyses of the S1 spike glycoprotein gene to investigate its genetic variability and the presence of viral subpopulations among vaccines, between batches, and also in each vaccine after a single passage was performed in chicken embryonated eggs. Our results revealed up to 13 amino acid substitutions among vaccines and some of them were localized in regions of the S1 glycoprotein that play a role in virus–host interaction. Secondary nucleotide peaks identified in the chromatogram for the S1 gene sequence revealed that all original vaccines (H120 and Ma5) were composed by different subpopulations of IBV. Moreover, new viral subpopulations were also found in vaccines after a single passage in chicken embryonated eggs. These findings indicate that H120 and Ma5 viral strains used in vaccines market in Brazil can still mutate very rapidly during replication, leading to amino acid substitutions in proteins involved in the stimulation of the immune response, such as the S1 glycoprotein. Therefore, our data suggest that the genetic variability of these viral strains should be taken into consideration to ensure an effective immune response against IBV.     

Dual Contribution of Mesenchymal Stem Cells Employed for Tissue Engineering of Peripheral Nerves: Trophic Activity and Differentiation into Connective-Tissue Cells

Adult peripheral nerves in vertebrates can regrow their axons and re-establish function after crush lesion. However, when there is extensive loss of a nerve segment, due to an accident or compressive damage caused by tumors, regeneration is strongly impaired. In order to overcome this problem, bioengineering strategies have been employed, using biomaterials formed by key cell types combined with biodegradable polymers. Many of these strategies are successful, and regenerated nerve tissue can be observed 12 weeks after the implantation. Mesenchymal stem cells (MSCs) are one of the key cell types and the main stem-cell population experimentally employed for cell therapy and tissue engineering of peripheral nerves. The ability of these cells to release a range of different small molecules, such as neurotrophins, growth factors and interleukins, has been widely described and is a feasible explanation for the improvement of nerve regeneration. Moreover, the multipotent capacity of MSCs has been very often challenged with demonstrations of pluripotency, which includes differentiation into any neural cell type. In this study, we generated a biomaterial formed by EGFP-MSCs, constitutively covering microstructured filaments made of poly-ε-caprolactone. This biomaterial was implanted in the sciatic nerve of adult rats, replacing a 12-mm segment, inside a silicon tube. Our results showed that six weeks after implantation, the MSCs had differentiated into connective-tissue cells, but not into neural crest-derived cells such as Schwann cells. Together, present findings demonstrated that MSCs can contribute to nerve-tissue regeneration, producing trophic factors and differentiating into fibroblasts, endothelial and smooth-muscle cells, which compose the connective tissue.