Control Of Other Diseases Research Articles

Historical review of schistosomiasis prevention and treatment in southern Anhui from 1950 to 1970

From 1950 to 1970, under the leadership of the central government, workstations for the prevention and control of schistosomiasis were established in the southern Anhui region. In terms of controlling the source of the disease, light and severe epidemic areas were scientifically divided. By opening new ditches to replace old ones, changing paddy fields to dry fields, and using traditional Chinese medicine and Western medicine to prevent the intermediate host of schistosomiasis, oncomelania from surviving. By managing the feces from human and animals and controlling the water source, the transmission route of schistosome eggs has been effectively cut off. At the same time, the education of hygiene awareness among susceptible populations were strengthened. In terms of diagnosis, modern physical and biochemical detection were used to improve the accuracy of diagnosis. In terms of treatment, by combining traditional Chinese medicine and Western medicine, together with the splenectomy, the cure rates were improved. In the process of preventing and controlling schistosomiasis, the governments of Anhui Province and the southern region of Anhui Province achieved good results, providing useful reference for the prevention and control of other diseases.

Electrocardiography in Bitches with Mammary Tumors

Background: The incidence of cancer has increased due to greater longevity of the animals as a consequence of better control of other diseases, improvement of nutrition and good practices in preventive medicine. Malignant tumors can cause paraneoplastic syndrome as hypercalcemia, anemia, cachexia, among others and consequent cardiovascular disorders. The electrocardiography (ECG) is a complementary exam that can reveal with its traces these rhythms disorders. Based on that, the objective of this study was to evaluate the ECG in bitches with mammary tumors in order to detect in which type of tumor would be found significant changes as in cardiac rhythm, ECG waves, segments or cardiac axis.Material, Methods & Results: Twenty-nine female dogs were used in this study, being 19 bitches with mammary tumor, and they were allocated in three groups: G1: control group (n=10), G2: benign neoplasia group (n=6) and G3: malignant neoplasia group (n=13). The most prevalent type of neoplasia in G2 was the benign mixed tumor (83%), followed by adenoma (17%) whereas in G3: carcinoma in mixed tumor (61%); papillary carcinoma (23%). Regarding cardiac rhythm, it was found sinus arrhythmia (SA) and normal sinus rhythm (NS): G1: 50% SA and 50% NS; G2: 67% SA and 33% NS; G3: 54% SA and 46% NS. No ventricular or atrial arrhythmias were detected. For other parameters in G1, G2 and G3, respectively (mean±Std error): FC (bpm): 110±9.2, 120±8.5, 124±7,5; P (ms): 48±1.6, 51±1.8, 50±1.2; P (mV) 0.19±0.02, 0,2±0.02, 0,19±0.02; PR (ms): 94±4.3, 93±5.5, 89±3.9; QRS (ms): 56±1.54, 60±4, 62±1.2; R (mV): 1.1±0.06, 1.2±0.24, 0.9±0.13; QT (ms): 203±9.4; 204±7.9; 182±15.6; and cardiac axis (°): 66±6.2, 61±7.9, 70±7.5. There were no significant differences for all cardiac parameters and also for ST interval and T wave morphology.Discussion: All electrocardiographic parameters found are in accordance with other studies carried out in the canine species. The results regarding tumor types differ from what was found in another study, in which in 18 bitches with mammary tumors, 55% were benign, with prevalence of adenomas (38%) followed by benign mixed tumors, and 45% malignant, with adenocarcinoma prevailing (22%). In another study, it was verified in 63 bitches the predominance of tubular carcinoma (26.56%) and carcinoma in mixed tumor (23.44%). Diverging from the electrocardiographic parameters of this study, a significant difference was found in the R wave amplitude value in the research by Barros et al., (2015) who performed computerized electrocardiography in 50 dogs, not only with mammary neoplasms (55% mammary carcinomas), but also in mastocytomas, lymphomas, benign tumors and other sarcomas. This author found out that the R wave amplitude values of the neoplasia group were lower when compared to the control group. In addition, we suspect that other types of tumors could result in more paraneoplastic syndrome than the mammary neoplasms found in this research. Neoplasms as lymphomas (T cells), apocrine gland anal sac adenocarcinomas, multiple myelomas and thymomas are known as a cause of hypercalcemia of malignancy and histiocytic sarcomas, myelomas, leukemia and lymphomas causing anemia. In conclusion, ECG has no changes in benign or malignant mammary tumors in dogs. However, this fact does not exclude the importance of its performance in pre-anesthetic evaluations.

Burden of schistosomiasis‐related mortality in Brazil: epidemiological patterns and spatial–temporal distribution, 2003–2018

To characterise the epidemiological patterns and the spatial-temporal distribution of schistosomiasis-related mortality in Brazil from 2003 to 2018. A national population-based ecological study that used official data from the Mortality Information System. The data included all deaths recorded in Brazil from 2003 to 2018 in which schistosomiasis was mentioned in the death certificate as an underlying or associated cause of death (multiple causes). The municipalities of residence were used as units of geographic analysis, and standardised and smoothed mortality rates (per 100000 inhabitants) were calculated using the local empirical Bayes method. Spatial autocorrelation was evaluated using global and local Moran indexes. To analyse the spatial dependence, the Getis-Ord G and Gi* statistics were used. During the study period, 18421113 deaths were recorded in Brazil. Schistosomiasis was mentioned in 11487 deaths (proportional mortality: 0.06%); for 8141 deaths (70.87%), it was listed as the underlying cause, and for 3346 deaths (29.13%), it was listed as an associated cause. The mean mortality rate was 0.38 deaths/100000 inhabitants. Individuals≥70years of age (RR: 115.34, 95% CI: 68.56-194.03) and residents in the Northeast region (RR: 10.81, 95% CI: 5.95-19.66) presented higher risks related to schistosomiasis. Municipalities with high mortality rates were identified in all regions, and high-risk clusters were found in municipalities located in the Northeast and Southeast regions of the country. Schistosomiasis remains an important cause of death in persistently endemic areas in Brazil, particularly in those with a high prevalence of the disease and a marked parasite load.

An oral delivery system for controlling white spot syndrome virus infection in shrimp using transgenic microalgae

White spot disease (WSD) is a longstanding and serious viral disease of various shrimp species that has caused high mortality rates for many decades. Currently, there is no practical method to control this disease. Therefore, we have explored the development of a novel vaccine-based method to control this disease using transgenic algae. During infection by white spot syndrome virus (WSSV), the interaction between viral envelope proteins and cell surface protein receptors on target cells is the key step of viral entry and replication. Hence, transgenic lines of the green microalga Chlamydomonas reinhardtii harbouring a WSSV VP28 viral envelope protein were created as an oral delivery system for vaccinating shrimp. Two separate transplastomic lines containing wild-type and codon optimized gene sequences for VP28 were evaluated for recombinant protein levels. Only the codon optimized line gave rise to detectable VP28 in western blot analysis, which demonstrated that optimization for chloroplast codon bias improved the efficiency of expression and that the gene design produced a favourable RNA secondary structure with suitable free energy for translation. In addition, bile salt and acid tolerance tests demonstrated that this transgenic Chlamydomonas can tolerate mildly acidic (pH 5.0) conditions and 0.30% bile salts. These features indicated that algal cells are suitable for delivering viral antigens through a shrimp's digestive system. In WSSV infection experiments, the highest survival rate (87%) was recorded in shrimps fed with the codon optimized VP28 line mixed into their feed, indicating that this line could be employed in the control of WSSV spread in shrimp populations. This algal strategy offers a new, efficient, fast and less labour-intensive method for the control of other diseases in aquatic animals through oral delivery.

Towards eradication: adopting a community-directed intervention strategy in the prevention and management of malaria in Zimbabwe

Zimbabwe continues to struggle to eliminate malaria despite the availability of several global health initiatives to manage the disease There is little empirical evidence on how to achieve the integration of community level interventions in the context of malaria prevention and management and public health in general This monograph traverses the dangers posed by malaria as a disease within the Zimbabwean context It proposes and encourages the conducting of theory based research to generate appropriate data that can be used in the implementation of strategies aimed at eventual eradication of malaria and management and control of other diseases

Identification of conditions which lead to unjustified requests for emergency treatment of hypertensive patients.

Aim To determine most common factors making patients with high blood pressure seek professionally unacceptable treatment of hypertension at the Emergency Department. Methods The survey was conducted at the Emergency Department of the Primary Health Care in Gradačac on randomly selected 207 patients who requested medical help because of high blood pressure. For all patients arterial blood pressure and body mass index (BMI) were measured. A survey about knowledge and attitudes regarding habits that affect high blood pressure as well as the socio-economic conditions was made. Results Prevalence of 10.3% was found with regard to visits to emergency care by patients due to high blood pressure. Most patients, 127(61.4 %), were overweight and 36(17.4%) were obese. Patients who rarely controlled their blood pressure were more frequent visitors of emergency medical services. Stressful situation occurs as a factor in a variety of forms. The survey showed that 76 (36.7%) patients sought medical help even though they had no blood pressure values that required emergency care. Conclusion Poorly organized health care system with no continuous and comprehensive preventive promotional programs caused by inappropriate use of resources in health care. The reorganization of primary care with full implementation of family medicine and greater integration of family medicine with other levels of the health care system should provide a better control and treatment of other diseases such as hypertension.

The effect of fungicides applied pre-stem extension on septoria tritici blotch and yield of winter wheat in Ireland

Ireland has the potential to produce some of the highest winter wheat yields in the world, however due to the highly disease conducive environment fungicides are heavily relied upon to achieve these yields. These fungicides primarily target control of septoria tritici blotch (STB), which if left untreated can result in significant reductions in yield. Typically winter wheat fungicide programmes are comprised of four applications, the first of which is applied pre-stem extension (PSE). It has been suggested that applying fungicides at this stage in the crops development slows disease progression to the upper canopy (final leaves three, two and one) which is responsible for the majority of yield potential. This study tested the effect of different pre-stem extension fungicide treatments on STB severity in the upper canopy during grain filling and subsequent grain yield in field trials conducted at three Irish locations over three consecutive growing seasons (2012-2014). When applied as part of a typical foliar fungicide programme significant differences in levels of STB on the final leaf three were observed at growth stage GS83between the PSE treatments (P = 0.05), with the solo azole resulting in higher levels of disease compared to the other fungicide treatments. Despite these differences in STB control no significant differences were observed between the treatments in final yield (P = 0.44). This study shows there is no yield advantage to applying fungicides prior to stem extension for control of STB, however, if they are being applied for the control of other disease e.g. yellow rust careful consideration should be taken with regards to choice of fungicide to avoid increasing STB severity later in the season.

The “BIG FIVE” – A South African perspective on sustainable holistic internal parasite management in sheep and goats

Because we became an unintended world leader in the development of multiple anthelmintic resistance, South Africa has had to find, embrace and implement more sustainable and holistic methods of managing helminths in sheep. The problem has been to wean farmers off a heavy reliance on anthelmintics and to use a wide array of measures that require more management, in the face of inertia and attempts by some unscrupulous drug purveyors to block the needed changes. Packaging the available and proven measures into five practical sections helps to make the change more palatable and attractive to farmers. These sections are termed “The Big Five” and consist of firstly, host resistance and resilience: in the past we have concentrated too much on anthelmintic resistance (AR) and not enough on SR (sheep resistance). The motto must be “Stop Selecting Sissy Sheep!” To achieve this we can apply selection of rams by faecal egg counts (FEC) or FAMACHA, culling of ewes based on targeted selective treatment (TST) results, good nutrition, especially protein and trace elements needed to support immunity, enough exposure to worms for immunity to develop, and control of other diseases. Secondly, reducing parasite load: since the outcome of parasitosis is largely determined by numbers, this needs ongoing attention. This can be achieved by reducing the length of stay in a pasture, reducing the grazing pressure if this is not possible, increasing the time of absence from a pasture, especially at danger times, alternation with non-susceptible grazing species where possible, avoiding worm “hot spots” like grassed pens and leaking water troughs. Thirdly, evaluate pasture factors: the farmer and advisor have to consider the height (length) of grazing as it affects its risk for parasite transfer, the type (pasture species) as it will influence risk, the pasture slope affecting run-off and thus the suitability for larval survival, and the aspect (direction facing) should also be used to assess risk. Fourth, monitoring the situation: farm situations can be assessed by regular (monthly or bimonthly) pooled flock FECs, AR assessments using FEC reduction tests (FECRTs) or other measures, measures using TST like the 5 POINT CHECK, a weather watch to predict conditions favourable for larval development (rain, humidity, temperature) and grazing monitoring to assess developing dangers. Fifth, optimise drugs to be used: drug usage must be rationalised and minimised. Implement TST and TT (targeted treatment); read the label, follow instructions and check the spectrum covered; weigh the sheep, set dose according to the heaviest in the group and check the gun for accuracy and repeatability; target the most vulnerable (lambs and lactating or heavily pregnant ewes) for special attention; do not buy on cost alone and do not formulate (mix) own farm mixtures. By emphasising the “Big Five” we can encourage and enable farmers to implement four or more items in each section, and thus minimise the long-term effects of internal parasites on farm profitability. This approach has assisted with getting farmers to use sustainable, holistic internal parasite management (SHIPM) in sheep flocks. A reminder in the form of a poster to be hung on the wall of the farm office will help encourage continuous implementation.

Acceptability and effectiveness of the storekeeper-based TB referral system for TB suspects in sub-districts of Lilongwe in Malawi.

BackgroundEarly access to tuberculosis diagnosis and treatment remains a challenge in developing countries. General use of informal providers such as storekeepers is common. The aim of this study was to determine the effectiveness and acceptability of a storekeeper-based referral system for TB suspects in urban settings of Lilongwe, Malawi.MethodsThe referral system intervention was implemented in two sub-districts. This was evaluated using a pre and post comparison as well as comparison with a third sub-district designated as the control. The intervention included training of storekeepers to detect and refer clients with chronic cough using predesigned referral letters along with monitoring and supervision. Data from a community based chronic cough survey and an audit of health centre records were used to measure its effectiveness. Focus group discussions and in-depth interviews were carried out to document acceptability of the intervention with the different stakeholders.ResultsFollowing the intervention, the mean patient delay appeared lower in the intervention than comparison areas (2.14 weeks (SD 5.8) vs 8.8 weeks (SD 15.1)). However, after adjusting for confounding variables this difference was not significant (p = 0.07). After the intervention the proportion of the population diagnosed with smear positive TB in the intervention sites (1.2 per 1000) was significantly higher than in the comparison area (0.6 per 1000, p<0.01) even after adjusting for sex and age. Qualitative findings suggested that (a) the referral letters triggered health workers to ask patients to submit sputum for TB diagnosis (b) the approach may be sustainable as the referral role was linked to the livelihood of the storekeepers.ConclusionThe study suggests that the referral system with storekeepers is sustainable and effective in increasing smear positive TB case notification. Studies that assess this approach for control of other diseases along with collection of specimens by storekeepers or similar providers are needed.

Porcine Circovirus Diseases: A review of PMWS

This article is a review on post-weaning multisystemic wasting syndrome (PMWS), the first described disease among the porcine circovirus diseases (PCVD). Post-weaning multisystemic wasting syndrome has, since its appearance in Canada in 1991, been seen in all major pig producing countries. To diagnose PMWS at herd level typical clinical appearance consisting of wasting and increased mortality must be combined with finding at autopsy of diseased pigs, where typical microscopic findings in the lymphatic tissue must be present. Post-weaning multisystemic wasting syndrome significantly increases the mortality and reduces the daily weight gain in weaner pig and/or in finishing pigs. Post-weaning multisystemic wasting syndrome can be transmitted by pig-to-pig contact and some studies point at airborne transmission as a possibility. Studies in Europe have shown several risk factors that either increase or decrease the risk for a pig herd to be affected by PMWS. At the pig level, studies have shown the importance of maternal immunity as protection for subsequent development of PMWS. To control PMWS, good production management and control of other diseases are crucial. Since 2004, commercial vaccines against Porcine Circo Virus type 2 have been coming on the market and many studies have shown great benefits of these to control PMWS. Today, sow vaccines as well as piglet vaccines are available in most countries. An extensive meta-analysis of many of the vaccines has shown a comparable good efficacy of the vaccines in significantly reducing mortality and increasing weight gain of the pigs.

Tan spot: a new disease of pyrethrum caused by Microsphaeropsis tanaceti sp. nov.

The isolation frequency of Microsphaeropsis sp. in spring in association with necrotic lesions on leaves in Tasmanian pyrethrum (Tanacetum cinerariifolium) fields has increased substantially since first identification in 2001. Examination of morphological features and sequencing of the internal transcribed spacer region (ITS) resulted in the identification of a new species, herein described as Microsphaeropsis tanaceti sp. nov. The pathogenicity of three M. tanaceti isolates to two pyrethrum cultivars was confirmed by inoculating glasshouse‐grown plants in three experiments. No significant differences in the susceptibility of the two cultivars to infection by M. tanaceti were found. Symptoms were tan‐coloured spots which coalesced around the margins of the leaves. Therefore, the name ‘tan spot’ is proposed for this new disease of pyrethrum. The sensitivity of seven M. tanaceti isolates to difenoconazole and azoxystrobin, commonly used fungicides for the management of foliar diseases in spring, was assessed under in vitro conditions. Sensitivity testing for difenoconazole was conducted using a mycelial growth assay on potato dextrose agar, whilst testing for sensitivity to azoxystrobin used a conidial germination assay on water agar. Microsphaeropsis tanaceti was found to be more sensitive to azoxystrobin than difenoconazole, with complete inhibition of conidial germination at concentrations above 0·625 µg a.i. mL−1. By comparison, concentrations of 50 µg a.i. difenoconazole mL−1 or greater were required for significant inhibition of mycelial growth. It therefore appears likely that there is currently some control of tan spot as a result of the use of azoxystrobin and to a lesser extent, difenoconazole, for the control of other diseases.

Evaluación de la información sobre actividad sexual proporcionada a pacientes con síndrome coronario agudo

It is common for the nursing staff to report on aspects such as feeding, medication, physical activity, control of other diseases, toxic habits and driving in the acute phase of acute coronary syndrome (ACS). However, we overlook such a vital aspect of the human being such as sexuality. Thus, we propose the following objectives: 1. describe the information provided to the patients diagnosed of ACS on possible sexual alteration; 2. evaluate the demand for information by the patients on how their disease will affect their sexual activity; and 3. evaluate the patient's interest in receiving this information. A descriptive study has been performed on 55 patients admitted to the Coronary Unit between November 2004 and April 2005, who were diagnosed of ACS after 72 hours by means of a self-administered questionnaire. A total of 89.1% were male with mean age of 55 years and 63.3% had not received information and thought that the stroke would not affect their sexual life, 55.6% being concerned. A total of 7.4% thought that they could reinitiate their sexual activity at 6 months while 9.3% thought that it could never happen. 1. Most of the patients had not received information on possible alterations in their sexual activity. 2. Most wanted to have information before the discharge and a minority did not consider that it was important to have information on the subject for different reasons. 3. The young subjects were the most interested in acquiring knowledge due to the importance they gave to their sexual activity.

Clinical pharmacy cardiac risk service for managing patients with coronary artery disease in a health maintenance organization

A clinical pharmacy service for managing the treatment of coronary artery disease in a health maintenance organization is described. Despite the proven benefits of aggressive risk factor modification for patients with coronary artery disease (CAD), there remains a treatment gap between consensus- and evidence-based recommendations and their application in patient care. In 1998, Kaiser Permanente of Colorado developed the Clinical Pharmacy Cardiac Risk Service (CPCRS) to focus on the long-term management of patients with CAD to improve clinical outcomes. The primary goals of the CPCRS are to increase the number of CAD patients on lipid-lowering therapy, manage medications shown to decrease the risk of future CAD-related events, assist in the monitoring and control of other diseases that increase cardiovascular risk, provide patient education and recommendations for nonpharmacologic therapy, and act as a CAD information resource for physicians and other health care providers. Using an electronic medical record and tracking database, the service works in close collaboration with primary care physicians, cardiologists, cardiac rehabilitation nurses, and other health care providers to reduce cardiac risk in the CAD population. Particular attention is given to dyslipidemia, blood pressure, diabetes mellitus, and tobacco cessation. Treatment with evidence-based regimens is initiated and adjusted as necessary. Over 11,000 patients are currently being followed by the CPCRS. A clinical pharmacy service in a large health maintenance organization provides cardiac risk reduction for patients with CAD and helps close treatment gaps that may exist for these patients.

Occurrence of Salmonella serotype Typhimurium DT104 on a commercial swine farm before, during, and after depopulation and repopulation

To determine whether depopulation-repopulation could be used to eradicate Salmonella serotype Typhimurium DT104 from a commercial swine farm in the midwestern United States. Observational study A commercial swine farm undergoing depopulation-repopulation to eliminate porcine reproductive and respiratory syndrome virus and Mycoplasma hyopneumoniae. Pooled fecal samples, tissue samples, and serum samples were collected from pigs on the farm before and after depopulation-repopulation. When there were no pigs on the farm, environmental swab specimens were collected for bacterial culture. Serum was analyzed for anti-Salmonella antibodies with an indirect ELISA. Salmonella isolates obtained by bacterial culture of fecal, tissue, and environmental samples were characterized by means of serotyping, phage typing, pulsed-field gel electrophoresis (PFGE), and antimicrobial susceptibility testing. 167 Salmonella isolates representing 9 serotypes were recovered from the farm. Results of PFGE and antimicrobial susceptibility testing suggested that S. Typhimurium DT104 strain was not eradicated from the farm. However, seroprevalence of anti-Salmonella antibodies and the percentage of pooled fecal samples positive for Salmonella spp were significantly decreased following repopulation. Results suggested that depopulation-repopulation in conjunction with stringent cleaning and disinfection, attention to biosecurity procedures, control of other diseases, and changes in feed management may reduce the occurrence of, but likely will not eliminate, Salmonella spp in commercial swine herds.

Appropriate vaccination and therapies for rural poultry flocks in developing countries and their relevance to developed countries

Rural poultry flocks in developing countries make little use of conventional vaccines or therapies. Appropriate vaccines must be robust, cheap and suited for local production in relatively unsophisticated laboratories. Only diseases producing high mortalities warrant attention. Appropriate therapies depend on local ethnoveterinary knowledge.Newcastle disease is the most important constraint to the productivity of village chicken flocks. The Australian Centre for International Agricultural Research (ACIAR) initiated projects on vaccines to control this disease in rural flocks in 1984. Thermostable variants of the avirulent strains V4 and I-2 were developed and shown to be safe and effective in laboratory and village trials. Master seed of I-2 vaccine is made available without cost to developing countries. Vaccine is produced by a seed-lot system and involves allantoic sac inoculation of non-SPF eggs. Harvested allantoic fluid is the basis of the vaccine. Sustainable vaccination campaigns require components other than an appropriate vaccine. Appropriate extension messages must be developed to target the neglected village flocks, and the women who usually control them. Systems of cost recovery must be developed. Appropriate training must be available at all levels – to administrators, laboratory staff and village vaccinators. With the control of Newcastle disease, villagers can be convinced of the full potential of their flocks to produce food and income. Other interventions including housing, nutrition and control of other diseases can be introduced.The thermostable vaccines have been tested in at least 30 developing countries and produced on a large scale in at least 9. International agencies other than ACIAR and various NGOs have supported the projects. The next village vaccine could be fowlpox, with virus adapted to production in the allantoic cavity.The major killing disease of duck flocks in Asia is duck plague. An ACIAR project has seen the development of an improved vaccine in Vietnam The vaccine, adapted to grow in cultured chick embryo fibroblasts, is registered foe use throughout Vietnam. Various remedies, mainly herbal, are used on village flocks to improve performance. These probably do not assist in treating established disease.The commercial industry could ask, are our vaccines too sophisticated and expensive, is there a place for food vaccines, should we investigate herbal remedies and how can we help the rural poor?

The Pan American Health Organization: Its Structure and Role in the Development of a Palliative Care Program for Latin America and the Caribbean

In recent years palliative care has emerged as a major public health care issue, both in developed and developing countries. The rising number of cancer deaths as a result of increased tobacco consumption, control of other diseases, lack of preventive programs, and the difficulties of accessing curative treatments in many countries have made palliative care and pain relief the appropriate, and in many cases, the only option for patients with advanced disease. The World Health Organization (WHO) and its Regional Office for the Americas, the Pan American Health Organization (PAHO), have promoted palliative care as a component of their cancer control program. Some health care workers and policy makers are not adequately informed about the role that intergovernmental agencies such as WHO and PAHO play in the health care field. This has led to confusion and, in some cases, misjudgment of the organization. This paper summarizes the structure and role of PAHO and, specifically, its participation in the development of a palliative care program for Latin America and the Caribbean. Many health care professionals, administrators, and policy makers are unaware of the organization's objectives in this area and the tools available to assist in the implementation and development of national programs to care for patients with advanced cancer. The information in this paper is based on data found in the PAHO and WHO web sites, as well as other technical publications from different sources, including individuals not formally associated with WHO or PAHO.

Malnutrition, age and the risk of parasitic disease: visceral leishmaniasis revisited

Children are said to be at greater risk of developing visceral leishmaniasis (VL) when they are younger and more malnourished. If malnutrition really is associated with VL, this potentially fatal and visible disease may be a general indicator of community health among the rural and suburban poor. Previous conclusions reached about the roles of malnutrition and age in VL epidemiology are questionable because they may have been confounded by transmission rate, because they have not been able to distinguish between different mechanisms of acquiring immunity, and because empirical observations have not been compared with theoretical expectations. Here we offer a framework with which to investigate these questions quantitatively, and do so with published data from endemic areas of Brazil. We conclude that children are indeed more susceptible to VL when they are younger and more malnourished, but it remains unclear whether the immunity to VL acquired with age is always acquired as a result of infection. The significance for leishmaniasis control, and for the control of other diseases associated with malnutrition, will depend on underlying mechanisms, which are not yet understood.

Block Residual Spraying of Premises with DDT for the Control of Malaria

Summary 1. All structures of 299 premises in a block of over 38 square miles in Wheeler Reservoir, North Alabama, were sprayed in June with approximately 200 mgm. of DDT per sq. ft., and a similar block was maintained as a control. Inspections of more than one-fourth of all premises in the two areas were made three times each month during July, August, and September and densities of A. quadrimaculatus recorded. The single application of spray markedly reduced the number of mosquitoes for a period in excess of three months. It appears from our observation that residual spraying of premises provides a more effective barrier to the transmission of malaria than does house spraying alone. 2. The study did not elicit any significant decline in mosquito density in the treated area as indicated by larval density, counts from keg shelters or the untreated surfaces of barns. 3. The added cost in this study of spraying all structures on premises was not in excess of one-third the cost of spraying the houses alone—$3.92 compared to $3.00. 4. The importance of treatment of large blocks of premises is emphasized. 5. On the basis of previous information on human blood feeding of A. quadrimaculatus and the present observation of almost complete elimination of this species within the premise by DDT residual spraying of all structures, it appears that complete DDT residual spraying offers more protection against malaria transmission than mosquito-proofing with its practical limitations. 6. Many beneficial side effects as regards a public health program result from the residual spray application including the control of other disease transmitting and pest insects.

The Harveian Oration

The Harveian Oration