In flux: Annual transport and deposition of suspended heavy metals and trace elements in the urbanised, tropical Red River Delta, Vietnam

Due to the depositional environment, river deltas are said to act as filters and sinks for pollutants. However, many deltas are also densely populated and rapidly urbanizing, creating new and increased sources of pollutants. These sources pose the risk of tipping these environments from pollution sinks to sources, to the world's oceans. We provide detailed seasonal and annual assessments of metal contaminants in riverine suspended particulate matter (SPM) across the densely populated Red River Delta (RRD), Vietnam. The global contributions of elements from the RRD are all <0.2% with many elemental fluxes <0.01%, suggesting the RRD is not a major source of elemental pollution to the ocean. However, 'hotspots' of metal pollution due to human activity and the impacts of tropical storm Son Tinh (July 2018) exceed both national level regulations and international measures of toxicity (e.g. enrichment factors). There is widespread 'extreme pollution' of Cd (enrichment factor >40) and concentrations of As higher than national regulation limits (>17 mg/Kg) at all sites other than one upstream, agricultural-dominated tributary in the dry season. These 'hotspots' are characterised by high inputs of organic matter (e.g. manure fertiliser and urban wastewater), which influences elemental mobility in the particulate and dissolved phases, and are potentially significant sources of pollution downstream. In addition, in the marine and fresh water mixing zone, salinity effects metal complexation with organic matter increasing metals in the particulate phase. Our calculations indicate that the delta is currently acting as a pollutant sink (as determined by high levels of pollutant deposition ∼50%). However, increased in-washing of pollutants and future projected increases in monsoon intensity, saline intrusion, and human activity could shift the delta to become a source of toxic metals. We show the importance of monitoring environmental parameters (primarily dissolved organic matter and salinity) in the RRD to assess the risk of transport and accumulation of toxic metals in the delta sediments, which can lead to net-increases in anthropogenic pollution in the coastal zone and the incorporation of toxic elements in the food chain.

[The rhythms of daily mitotic activity in Vigna radiata (L.) R. Wilczek]

The daily mitotic activity (MA) in Vigna radiata (L.) R. Wilczek. has been studied using local cultivar for Vietnam No I 176. It has been shown that the curve of mitotic activity has five peaks. Maximum mitotic index (MI) was observed at 04:00 (5.93 %) and the other peaks were at 02:00 (5.58 %), 08:00 (4.70 %), 12:00 (4.60 %) and at 22:00 (4.60 %). If we took into account that duration of the mitotic cycle in Vigna radiata makes up ten hours, we can propose that there are two peaks of MA within each cycle. It may be due to the presence of two meristematic cell subpopulations which enter mitosis at different time and have nearly equal duration of the cell cycle.

A study of edema disease in pigs in Vietnam with particular reference to the use of autovaccine for the prevention of disease

Edema disease caused by Escherichia coli is one of the most common diseases in postweaning piglets throughout Vietnam. Verotoxigenic E. coli (VTEC) was isolated from 197 of 261 samples (75.5%). All isolates were confirmed by basic biochemical tests and carbohydrate fermentation characteristics. Of these, 70.1% of isolates are hemolytic, 45% isolates belonged to serotypes O149:K91, possessed the VT2e gene, and was the most predominant VTEC pathotype associated with edema disease in pigs. Serogroup O139 accounted for 30% of the isolates, followed by serogroup O138 and O141 (25%). In addition to VT2e gene, the ST (72.7%) and LT (52.7%) genes were also recognized. A total of 10 representative isolates were subjected to toxigenicity testing by intraperitoneal injection in mice and experimental infection in pigs. It was shown that 100% of the mice were killed 17-24 h post injection (p.i.). All pigs experimentally infected with challenge strains and developed typical symptoms of edema disease 36-72 h p.i. A multivalent killed whole-cells vaccine containing aluminum hydroxide was prepared from 5 VTEC strains. The vaccine was 100% safe when administered by the intramuscular route into the pigs. A field trial for over 100,000 pigs (21-90 days old) showed that vaccinated pigs were protected against edema disease at a level of 90% compared to 100% of pigs from unvaccinated groups.

Antimicrobial Resistance Phenotypes of ETEC Isolates from Piglets with Diarrhea in North Vietnam

Both disk diffusion and broth micro-dilution assays were employed to determine the level of resistance in Enterotoxigenic Escherichia coli (ETEC) isolates (n = 170) obtained from preweaning piglet colibacillosis from the two different pig production systems (commercial piggeries and small holder farmers) in Vietnam. Overall, tetracycline, streptomycin, amoxicillin, trimethoprim/sulfamethoxazole, and chloramphenicol showed markedly higher rates of resistance. Both apramycin and ceftiofur are active against all ETEC isolates. These antimicrobials could be recommended as the drugs of choice for the treatment of E. coli infections in young pigs in North Vietnam. Resistance to third-generation cephalosporin (ceftiofur, ceftazidime, and cefoxitin) was not observed in Vietnamese ETEC isolates. Multiple resistances to greater than three antimicrobials were widely distributed (approximately 79.4%).

Management of childhood acute respiratory infections at private pharmacies in Vietnam

OBJECTIVE

To investigate the knowledge and practice among private pharmacy staff in Hanoi regarding case management of mild acute respiratory infection (ARI) in children.

METHODS

Sixty private pharmacies in Hanoi were randomly selected. Knowledge was assessed through interviews with pharmacy staff using a questionnaire; practice was assessed through the Simulated Client Method.

RESULTS

In the questionnaire, 20% of the pharmacy staff stated that they would dispense antibiotics. In practice, 83% of the pharmacies dispensed antibiotics. Only 36% of the cases were handled according to guidelines. In the questionnaire, 81% of interviewees stated that antibiotics are not effective in short therapeutic courses. In practice, 48% of the antibiotics were dispensed in courses less than five days. Traditional herbal medicines were dispensed in 41% of the encounters. In the questionnaire, 53% of the pharmacy staff stated that they would ask the patient about difficulty of breathing. In practice, questions related to difficulty of breathing were asked in less than 10% of the encounters.

CONCLUSIONS

Dispensing of antibiotics for mild ARI was common practice among private pharmacies, and there was a significant difference between knowledge and practice. Interventions are needed to improve pharmacy practice in Hanoi.

STD management by private pharmacies in Hanoi: practice and knowledge of drug sellers

BACKGROUND

Prompt treatment of sexually transmitted infections may reduce the incidence of HIV/AIDS infections. With health sector reforms private pharmacies are increasingly the first and only contact with health delivery services.

OBJECTIVES

To find out how patients with STDs are treated at private pharmacies in Hanoi, and what drug sellers know about STD management.

METHODS

Five simulated clients were taught to adopt a scenario stating that their friend had a urethral discharge. They visited 60 randomly selected private pharmacies in urban Hanoi and noted all questions asked, advice offered, and treatment given. Afterwards interviewers administered a semistructured questionnaire to all people working in the 60 pharmacies.

RESULTS

Drug treatment was given in 84% of the 297 encounters averaging 1.5 drugs and 1.2 antibiotics per encounter. Quinolones were given 188 times. No dispensing was adequate for chlamydia or was in accordance with the national guidelines. No questions were asked in 55% of encounters and no advice was given in 61%. Questions on sexual activity were asked in 23% (69) of cases and about the health of the partner twice (1%). Advice to practise safe sex was given in 1% of encounters and for the partner to seek treatment only once. Of 69 questionnaires administered 51% said they would refer to a doctor, 16% said they would ask about the sexual activity 1% said they would ask about the health of the partner, 7% said they would advise using a condom, and 1% advised telling the partner to seek treatment. Even after prompting, 61% would ask no questions and 80% would give no advice.

CONCLUSIONS

Even though 74% of pharmacists and drug sellers know that they should not treat STD patients, 84% actually did. None gave syndromically correct treatment. In both the questionnaire and during the simulated client methods, numbers advising on partner notification and condom use were very poor. Educational or peer awareness interventions are urgently needed among private pharmacists in Vietnam.

Compensatory hypertrophy in radiothyroidectomized dwarf rats

The aim of the study was to clarify whether growth hormone and thyroid hormones play a role in compensatory organ hypertrophy. Radiothyroidectomized dwarf rats with serious disorder of growth hormone production due to the loss of thyroid function were used in the experiments. As regards growth hormone production these animals may be considered as having been "hypophysectomized". The loss of thyroid function and growth hormone deficiency did not affect the degree of compensatory hypertrophy of the kidney, the adrenal and the gonad. The observation indicates that the hormones under study are not of decisive importance in the mechanism of compensatory organ enlargement. Further investigations are needed to clarify whether organ enlargement in the hypometabolic rat occurring at the level observed in the controls is associated with enhanced function.