Persistence and movement of phorate at high concentrations in soil

The entrance of a large number of chemicals into the agricultural market has caused concern to both cultivators and scientists because of their effectiveness at the target site, possibility of underground water contamination, and other undesirable effects such as phytotoxicity and effects on nontarget species. The persistence and movement of phorate--a systemic granular insecticide--were studied at high concentrations (4 and 8 kg a.i./ha) in field soil in two seasons, i.e., winter and summer. Periodic sampling for total phorate residues (TPR) at various vertical depths showed that it leached more efficiently at the higher dose (i.e., 8 kg a.i./ha) in both seasons. The horizontal mobility was also higher at this dose. Irrespective of the treatments, TPR leaching was significantly greater in winter with the higher dose, whereas its movement in the horizontal plane was comparatively greater in summer with this dose. The TPR concentration peaks remained stationary at 7.5 cm depth at all the redistribution times until the pesticide was nearly dissipated under both treatments and in both seasons. TPR persistence was higher at the higher dose. Its persistence was comparatively greater in winter than in summer. The present findings show that there seems to be no threat of underground water contamination by this pesticide even at a rate as high as 8 kg a.i./ha.

Rain splash dispersal of third-stage larvae of Cooperia spp. (Trichostrongylidae)

Laboratory investigations were designed to study the distribution of splash droplets caused by splashes of water on the surface of a cow pat. Laboratory and field experiments were designed to evaluate the possibility of water splash dispersal of third-stage Cooperia spp. larvae from cow pats to the surroundings. One incident drop of water 5 mm in diameter falling 2.2 m on a cow pat produced approximately 1,000 splash droplets. In still air, more than 90% of the splash droplets were found within 60 cm from the point of impact, and only a few travelled beyond 90 cm. After a latent period, incident drops of water 5 mm in diameter falling 2.2 m on a cow pat of 500 g, containing 450 third-stage larvae of Cooperia spp. per g feces, resulted in splash dispersal of larvae to a maximum distance of 63 cm from the point of impact; the majority of larvae were found within 21 cm. A field experiment confirmed that lateral splash dispersal of third-stage Cooperia spp. larvae during a shower can be very effective. On one occasion there was a splash dispersal of 4,851 third-stage Cooperia spp. larvae in 45 minutes to an area from 1 to 15 cm around the periphery of a cow pat of 500 g containing 120 third-stage larvae per g of feces. This corresponds to a dispersal of 8% of total.

Recreational water quality analyses of the Colorado River corridor in Grand Canyon

We intensively examined the recreational water quality of the Colorado River and 26 tributaries in Grand Canyon National Park over four consecutive summers. Highly ephemeral precipitation cycles and arid watershed hydrologies were the principal factors influencing water quality. Fecal coliforms (FC) in the river and in most tributaries were less than or equal to 10 FC 100 ml-1 and less than or equal to 20 FC 100 ml-1, respectively, during drought cycles. During rainfall cycles, FC densities were highly variable and often exceeded recreational contact standards. FC were not found to vary significantly in response to diurnal fluctuations in river stage height which resulted from hydroelectric stream flow regulation. River and tributary bottom sediments harbored FC in densities averaging 10 to 100 times those in the overlying waters. Sediment FC densities were not found to be reliable indicators of overlying water quality when storm flow and nonstorm flow periods were compared.

Seasonal changes in pasture populations of infective larvae of gastrointestinal nematodes of cattle in eastern Nigeria

The seasonal changes in the populations of trichostrongylid infective larvae (L3) on herbage and in soil samples collected from pastures grazed by beef cattle were studied at Nsukka, eastern Nigeria, from April 1980 to July 1981. Large numbers of L3 were recovered from all samples collected during the rainy season (April to October). The rainy season herbage infestation was characterised by three clearly defined peaks. The first, which followed an 'early rains' (April) rise, occurred in the second half of May while the larger second and third peaks occurred in late July and October respectively. It is suggested that each of these peaks represented a distinct wave of infestation by a separate generation consisting of the three trichostrongylids concerned, namely Cooperia, Haemonchus and Trichostrongylus species. Although there was a sharp fall in pasture infestation following the onset of the dry season, appreciable numbers of L3 were still present on herbage in early December. The implications of these findings have been discussed in relation to the choice of effective strategic anthelmintic programmes for the prophylaxis and control of bovine parasitic gastroenteritis in the Nsukka area.

Development and survival of infective larvae of gastrointestinal nematode parasites of cattle on pasture in eastern Nigeria

A study of the development and survival of the infective larvae of the common strongylate nematodes of cattle at Nsukka, eastern Nigeria, from September 1981 to March 1982 showed that the dry season (November to March) was generally unfavourable for preparasitic development and survival of Cooperia, Haemonchus and Trichostrongylus species. However significant development may occur during the last two months of the season as a result of the small amounts of rain that usually fall at that time of the year. It was shown, using tracer goat kids, that only paddocks contaminated late in the dry season were infective at the start of the rainy season and that March contamination, in particular, is an important source of the 'early rains' (April/May) rise in herbage infestation commonly observed.

Reinfection and infection rates of ascariasis in relation to seasonal variation in the Philippines

Stool examinations of 320 primary school children for eggs of Ascaris revealed a prevalence of 74.0 percent. Reinfection and infection rates were determined on a monthly basis with egg-positive subjects treated correspondingly. Due to dropouts of subjects, only 154 children completed the 12-month observation. About 15% of children remained negative after treatment during one year but 85% got reinfected, with those reinfected only once being the highest then those reinfected twice, followed by those reinfected more than twice in a year. Of the 203 Ascaris worms collected 69% were females and 31% were males with a sex ratio of 2.4 females to one male; 73% were mature and 27% were immature females; 70% were mature and 30% were immature males; mean number of worms per child was 2.6. The mean length and weight of female was 22.9 cm and 3.6 gms respectively while for males it was 16.1 cm and 1.7 gm respectively. The graph showing amount of rainfall, reinfection and infection rates of ascariasis revealed the presence of two major peaks both in the reinfection and infection rates noted in December-January and May-June. Likewise, the rainfall also peaked twice namely in August and October. It appears that ascariasis reinfection or transmission is highest when rainfall is minimal and lowest when rainfall is at its highest peak. Based on the peaks of reinfection and infection, it is suggested the school children be dewormed in June and in December each year for at least three years.

Performance of Canadian Holstein-Friesian cattle in the humid forest zone of Ghana. II. Preweaning performance

Birth weights, weaning weights and average daily gains of 97 calves born to 27 Holstein-Friesians imported from Canada were used. Adjusted mean birth weight, weaning weight and daily gain were 35.6, 104.6 and 0.5 kg respectively. Of the three variables studied sex of calf significantly influenced only birth weight whereas season of birth, sire of calf, parity of dam and year of birth significantly influenced weaning weight and daily gain but not birth weight. Sex, season, sire, parity and year all together accounted for 18.35, 43.49 and 46.09% of the variation in birth weight, weaning weight and daily gain respectively. Birth weight increased by 0.29 kg/day increase in gestation length and 0.027 kg/kg increase in calving weight, whereas weaning weight increased by 1.31 kg/kg increase in birth weight. Birth weights, weaning weights and daily gains observed here are similar to previous reports from other tropical environments.

Toxic effects of acid rain on aquatic and terrestrial ecosystems

The historical perspective as well as the nature and causes of acid precipitation are presented. The toxicological effects of acid precipitation on lakes, other water bodies, fish, and invertebrate fauna are reviewed. In addition, the effects of this phenomenon on soil productivity and forest growth are examined. It appears that grave toxic effects have been and are being experienced by aquatic systems, but there is little reliable evidence of economic damage to crops, natural vegetation, and soil and biological processes. There may be insidious long-term effects on terrestrial ecosystems, particularly in the more susceptible areas.

Acid rain and soil

A summary of important chemical properties of soil is given and the way in which acid rain may affect these properties is discussed. Acid rain may suppress microbiological decomposition and nitrification processes, thus influencing the nutrient status of soils. It has also been found that soil organic matter is less soluble in more acid solutions. Changed nutrient availability patterns are predicted in a low pH environment and enhanced leaching of essential elements from the soil exchange complex has been observed. Increased solubility of potentially toxic elements such as aluminium may also occur from soils which have been exposed to acidified rainfall.

Internal parasitism in milk goats in Kenya

Observations were made on individual cases and on herds showing the effects of internal parasitism on the health and productivity of Toggenberg and Saanan goats. The clinical reactions varied markedly being influenced by the degree of infestation and duration of illness. Typical cases showed emaciation, anaemia, oedema, weakness and sometimes diarrhoea and death. Faecal analyses were dominated by strongyle egg counts which rose progressively throughout the study period. Overstocking led to some animals being at greater risk.

Tsetse and trypanosomiasis survey of Southern Darfur province, Sudan. II. Entomological aspects

Atsetse survey of Southern Darfur province, Sudan showed that the distribution of the only species present, Glossina morsitans submorsitans, had not appreciably altered over 10 years. Fly populations are most dense south of the Wadi Umbelasha but light infestations are found in the woodlands north of this riverine system to a latitude of about 10 degrees 15' N. Data are given on host availability which is thought to be the major factor determining tsetse distribution. The relative importance of tsetse and of tabanids as transmitters of bovine trypanosomiasis in the province is discussed. The evidence indicates that tsetse are very much more important and that cattle are most at risk of contracting infections during their dry season southerly migrations to the tsetse belts especially during their "Rushash" migration at first rains. Possibilities of tsetse control are discussed but in the short term trypanosomiasis control is most likely best achieved by chemical prophylaxis/therapy of cattle at risk.

Rainfall and birthweight distribution in rural Tanzania

Seasonal variations in birthweights over a 10-year period are compared with the local rainfall pattern in a rural area of Tanzania. Mean birthweight falls by about 60 g in the course of the rainy season. Lagged regression analysis reveals a negative impact of rainfall on birthweight after 3 months. Deviations from average rainfall show a positive correlation with birthweight after 4 months, but only in the months when rainfall is critical for food crop production. The interactions of these contrary effects are held responsible for the sudden fluctuations in mean birthweight that were observed.

The iodine status of grazing sheep as monitored by concentrations of iodine in milk

The iodine nutrition of grazing ewes was assessed from milk iodine concentrations. In 54 flocks sampled throughout Victoria, the mean milk iodine concentrations in ewes ranged from 79 to 1831 micrograms/l. In 2 flocks where newborn lambs had goitre the concentrations in ewes ranged from 45 to 98 micrograms/l. A marked seasonal variation was apparent when ewes in a flock were sampled at monthly intervals over 2 years. Milk iodine concentrations were highest at the end of summer, and were lowest in spring. In grazing ewes the milk iodine concentrations remained relatively constant throughout the day. In ewes given single oral doses of up to 2 mg iodine, milk iodine concentrations increased to maximum within 5 h, the increment being related to the dose administered, and decreased to pretreatment concentrations within 24 h. Milk iodine concentrations in ewes given 1 ml iodised oil intramuscularly remained significantly higher than untreated ewes in the same flock for 16 months after treatment. The effectiveness of the single injection was still apparent after 2 consecutive pregnancies in the ewes.

Meningococcal disease and season in sub-Saharan Africa

The incidence of meningococcal disease varies seasonally in both tropical and temperate countries. This association is most apparent in sub- Saharan Africa, where almost all epidemics start in the dry season and abate during the rains . Meningococcal carriage rates do not vary with season either in Africa or in temperate countries, suggesting that seasonal factors have little influence on the frequency of meningococcal transmission. It is suggested that changes in the ratio of clinical to subclinical cases of infection are more important than changes in the frequency of transmission in producing seasonal variations in the incidence of meningococcal disease. Some evidence to support this hypothesis was obtained during an epidemic of group A meningococcal disease in northern Nigeria in 1977-79.

Basic epidemiological aspects of acute gastro-enteritis in a regional hospital in Kuwait

Over a 12-month period 1045 children were hospitalized because of acute gastroenteritis. The disease accounted for 26% of admissions and for 20% of the total bed utilization. Prevalence peaked twice (autumn and spring), was low during summer and lowest in winter. Only 20% of children were breastfed on admission and in the great majority of those who were not, breast feeding was stopped under the age of two months. Early cessation of breast feeding may be responsible for the increased frequency of gastroenteritis in very young infants, and should be a cause for major concern in developing countries.

Melioidosis in Far North Queensland. A clinical and epidemiological review of twenty cases

During the last 4 years, 20 cases of clinical melioidosis were diagnosed in the geographical area between Tully and Thursday Island. Sixteen were diagnosed by culture of Pseudomonas pseudomallei, and four by positive serology with appropriate clinical features. Most cases occurred during or after a heavy wet season. All patients were adult, and males predominated. Farmers and stockmen represented predisposed populations due to their prolonged soil contact. Ten patients were white Australians, six were Aborigines and four were Torres Strait Islanders. Twelve cases were first diagnosed by positive blood culture and four by sputum culture. The primary site of infection was pulmonary in 14 cases, genitourinary tract in one case, subcutaneous tissues in one case, and joints in two cases. In cases of fulminating infection metastatic abscesses were commonly found in many organs; typically lungs, liver, kidneys and spleen. Six patients had acute fulminating disease and died. Fourteen patients successfully responded to appropriate therapy, but relapse occurred in three, all of whom had an alcohol problem and showed poor drug compliance. The presence of diabetes mellitus in six patients confirmed the important known association of these two diseases. In three fulminating and four subacute infections the serology was negative at the time of diagnosis by culture. Antibiotic therapy for the different forms of this disease is reviewed, and a laboratory protocol for the rapid reporting of positive culture results is included.

Serological prevalence of bovine babesiosis in Mali

A serological survey of cattle in Mali was carried out to determine the prevalence of antibody activity to Babesia bovis and B. bigemina. It was found that the level of B. bovis infection as indicated by antibody activities was too low to be of immediate concern. However, the serological prevalence of B. bigemina was high and this may indicate a potential disease problem. It was also found that when zebu and N'Dama cattle grazed together the N'Dama were twice as likely to have positive titres to Babesia as were the zebus.

Time variation of radon daughters concentration in snowfall

Time variation of radon daughters concentration in snowfall was measured continuously. The relations of radon daughters concentration in snowfall to the precipitation and to atmospheric radon daughters concentration were investigated. It has become clear that when precipitation is small, radon daughters concentration in snowfall is distributed in a wide range, and that the quantity of radon daughters brought to ground surface by snowfall is proportional to precipitation. Washout effect of the snowfall on atmospheric radon daughters was also investigated.

Airborne pollen sampling in Manoa Valley, Hawaii: effect of rain, humidity and wind

Kramer-Collins pollen sampling was conducted over 24 hours for 25 consecutive months at two valley sites in Honolulu. Of 1,059 expected samples, 699 (66.0%) were collected. Only 25 were considered excellent, i.e., eight three-hour collection bands. Twenty eight were considered good, ie., two to six bands. The difficulties in the study were associated with the weather directly (17.5%), the power source (3.9%), inadequancy of the samplers (63.1%) and the inexperience of technicians (15.3%). Sampler problems were also indirectly attributable to the high humidity, rain and wind, which differed at the two sites.

Boophilus microplus tick burdens on grazing cattle in Colombia

This study was conducted at Carimagua Research Centre in a well-drained savanna area in the eastern plains of Colombia. The objectives were to note the effect of ecological factors on tick burdens, principally the effect of the environment given by four grasses on the seasonal variations of tick populations. Adult female tick counts were carried out on heifers grazing four pastures and tick larvae on the grass detected by cloth dragging. Tick counts were significantly higher on animals grazing Brachiaria decumbens than those grazing Andropogon gayanus, Melinis minutiflora or native pastures. Tick larvae counts on the grass showed a similar tendency. Introduced grasses and intensification of production will require greater care to control tick infestations since increases in stocking rate and ground coverage could augment tick populations.

Seasonal variations in nutrition among a group of nomadic pastoralists in Niger

To identify the most critical period in a normal year for nomadic Sahelian pastoralists, 54 families of Wodaabe herders in Niger were visited every 3 months for a year. At each visit an average of 366 herders were interviewed with a standard questionnaire and anthropometric measurements were made. A cohort of 32 adult men lost a mean 3.1 kg between February and May, the peak of the dry season, and 30 adult women lost a mean 2.4 kg during the same period. Both men and women regained weight progressively over the months until the next February. Children under 5 years not only stopped gaining weight between February and May but on average lost 113 g; after May normal rates of weight gain resumed. This weight loss caused an increase in the proportion with acute malnutrition (less than 80% reference median weight-for-height) to 17% in May from 7% in November.

The effect of aldicarb on nematode population and its persistence in carrots, soil and hydroponic solution

Aldicarb, Temik 15 G, was incorporated in furrows at 3.37 and 6.73 kg ai (active ingredient)/ha and carrots (Daucus carota L.) were directly seeded on the same day. The numbers of nematode larvae were significantly suppressed in the treated plots; averages were 249, 74, and 51/50 cc soil samples for control (0), 3.37 and 6.73 kg ai/ha, respectively. Aldicarb treatment resulted in a 28% yield increase as compared to the untreated. Aldicarb residue in carrots was 28 ppb for the low treatment and 46 ppb for the high. Residual levels in soil of high treatment declined from 61 to 31 ppb during two weeks prior to harvest, meanwhile, those in the low decreased slightly from 13 to 12 ppb. Carrots placed in hydroponic solution containing aldicarb 14.5 ppm for 6 days, had an aldicarb residue of 10.26 ppb and the hydroponic solution, 2.7 ppb. Persistence of aldicarb residue was in carrot greater than in soil greater than in hydroponic solution.

Weight-for-height nutrition surveys in rural Kwazulu and Natal, July 1983

South Africa experienced a severe drought in 1982/1983. In July 1983 certain rural communities were identified which had recorded the most severe drought. Children were selected at random from these areas and compared against controls with regard to their respective weights and heights. On the basis of the predetermined sample sizes employed, no significant difference between the groups could be demonstrated. When compared with certain urban children attending crèches in Pretoria, there was also no significant difference. It is concluded that in July 1983 no crisis as regards the prevalence of acute malnutrition in children aged 1-5 years existed in the communities tested.

Field studies on Bulinus senegalensis Muller and the transmission of Schistosoma haematobium infection in a Gambian community

Seasonal changes in populations of Bulinus senegalensis were studied in temporary pools on the Senegambian plateau. The first snails to appear had survived aestivation and had a mean height of 3 mm. Thereafter two patterns of change in snail numbers and size were observed probably related to differences between pools in snail mortality rates. The prevalence of patent schistosome infections appeared to be related to the inferred differences in snail mortality rates. The prevalence and intensity of human Schistosoma haematobium infection was greatest in villages near large pools where snail populations had relatively low schistosome infection rates compared with that in a small, shallow pool. Differences in patterns of water use are an important determinant of the intensity of human infection as well as differences in the infection rate of snails in the nearby pool. Differences between years in the rate of acquisition of S. haematobium by children were observed, with little transmission occurring in a year when mid-season rainfall was deficient. There were significant differences between villages in the annual variations of transmission.

Survival of infective larvae of nematode parasites of cattle during drought

In a study originally designed to determine the seasonal origin of the high levels of availability of nematode larvae to cattle in winter and spring, plots were serially contaminated with eggs of Ostertagia ostertagi and Cooperia oncophora by naturally-infected calves at monthly intervals from February 1980 to September 1980. The availability of infective larvae was monitored by monthly pasture sampling and larval recovery. Because of the intervention of a 15 month drought, recoveries of larvae from the pastures were very low until March 1981 (autumn in Australia) when large numbers of larvae appeared on pastures contaminated in the preceding spring. Examination of dry dung pats at that time showed that significant numbers of larvae were present in pats deposited up to a year previously, and particularly in pats deposited in May, August and September. Following the resumption of normal rainfall in May 1981, larval numbers in pats rapidly declined and concentrations of larvae on the pastures increased to extremely high levels. It is suggested that survival of infective larvae in dry dung pats was enhanced by the drought, with implications for control of nematode infections of cattle, particularly in winter rainfall environments.

Infection rates of respiratory syncytial virus in pediatric patients attending Phra Mongkutklao Hospital, Bangkok

Respiratory syncytial virus (RSV) and other pathogens were isolated from nasopharyngeal secretions from 200 pediatric patients attending the Out Patient Department of Phra Mongkutklao Hospital with symptoms of upper respiratory tract infections. Their sera were also taken for determination of class specific immunoglobulin antibody titers. The positive isolation rates were 36% for RSV, 5.5% for adenovirus 1.5% for herpes simplex virus (HSV), and 4% for Staphylococcus aureus. One to 5.5% of these patients had mixed infection. Ninety five percent of patients with positive RSV isolations had IgM antibody which was found only in 30.7% in patients with negative RSV isolations. This result indicated that RSV was likely to be the most common pathogen responsible for the upper respiratory tract infections in children in Bangkok during the rainy season.

Environmental factors in the etiology of endemic elephantiasis of the lower legs in tropical Africa

The environmental factors including geography, geology and soil have been reviewed in areas of high prevalence of non-filariasis endemic elephantiasis surveyed in tropical Africa. These areas occur at altitudes above 1000 m where rainfall is seasonal and exceeds 1000 mm annually. The soil is a red clay, very slippery when wet and very adhesive if allowed to dry on the skin. These are also areas of past or present alkalic volcanism, the prevalence being highest in proximity to the volcanoes. The derived soils are notable for the high proportion of alumino-silicate particles of colloid size in the clays. The significance of these findings suggests that the number and small size of the clays. The significance of these findings suggests that the number and small size of the particles facilitates entry through the skin into the lymphatic tissues, where they exert the known irritant and fibrosing effects of silica and alumina.

Uptake of 2,4-D in higher plants from artificial rain

Sinapis alba L., Lapsana communis L., Achillea millefolium L., Brassica napus L., Lactuca sativa L., and Lycopersicum esculentum L. were exposed to 2,4-dichlorophenoxy [2-14C]acetic acid (2,4-D) at 10 micrograms liter-1 in artificial rain, pH 6.5 and 3.3. The 2,4-D was absorbed in all species tested. Concentrations of parent 2,4-D appeared at the highest level in Achillea (0.1 mg kg-1 dry wt), and at zero level in Lycopersicum. Twenty-one daily treatments at pH 6.5 for 30-min periods increased dry-matter concentrations (P less than or equal to 0.05) in the leaves of Achillea and decreased those in Brassica. No change in dry-matter concentration was observed in the leaves of Brassica by seven daily treatments for 30-min periods at pH 3.3.

Distribution of fallout cesium-137 in Hawaii

The concentration of 137Cs was determined by gamma spectrometry in soils and surface-deposited volcanic sublimates from various climatic locations on the islands of Hawaii, Oahu and Maui. A distinct pattern of higher concentrations on the wetter windward sides of the islands and a correlation between 137Cs concentration and amount of rainfall were observed, which confirm the source of the 137Cs as atmospheric fallout. In the soils, the concentrations measured (to 1.93 pCi/g) are within the range reported for the continental United States and other mid-latitude locations in the northern hemisphere. In the basaltic lavas, the concentration of 137Cs was found to be variable but was overall very low, and is apparently controlled by the porosity and permeability of the lavas in addition to rainfall.

Kala-azar in south-west Ethiopia: seasonal variation in disease occurrence

In a 12-year retrospective study of patients with kala-azar from Gidole Hospital in south-west Ethiopia it is demonstrated that most patients are diagnosed during the months August to November with another small peak from March to May. It is suggested that transmission is associated with two main periods of annual rainfall.

Cerebral malaria in Tanzania. Its epidemiology, clinical symptoms and neurological long term sequelae in the light of 66 cases

A neurological study of 66 patients with the cerebral form of Plasmodium falciparum malaria is presented. The patients were diagnosed, treated and re-examined at the Mnero Hospital, south-east Tanzania. Epidemiological aspects, neurological symptoms and the results of re-examination within six months of discharge from hospital are described. Although the mortality rate was low, some degree of neurological disability could be detected in a number of children at the follow-up examination.

Rainsplash as a mechanism for soil contamination of plant surfaces

We characterized the physical transport of soil, and therefore contaminants attached to the soil, onto vegetative surfaces due to rainsplash. Soil accumulation by tomato plants (Lycopersicon esculentum) was investigated as a function of soil particle size, rainstorm characteristics, foliage height, surface area and canopy cover of the plants. No soil particles greater than 105 micron in diameter were detected on the plants. Most of the soil was splashed no higher than 40 cm above the ground surface. Linear relationships were observed for concentrations of less than 53 micron soil on vegetation and certain rainfall characteristics. Data from this study, as well as ancillary calculations, provide evidence that a significant fraction of surficial contamination of foliage may be attributed to the rainsplash mechanism.

Reconstruction of environmental tritium levels from wine analysis

A correlation between precipitation and wine tritium concentrations was observed following a three-year study carried out within two Hungarian wine-growing districts. It was found that wine tritium, i.e., in the grape berry at harvest, reflects the preceding environmental tritium levels, as presented by the time-weighted average of the local precipitation tritium concentrations. This relationship--also supported by other studies--is explainable by a simplified model of water transport in the soil-plant-atmosphere system. Reconstruction of past environmental levels cannot be performed using the applied formula but a formal relationship between the wine data and the preceding 12 months' average precipitation tritium concentrations could be established. This was tested by comparing Hungarian wines of known date with precipitation data pertaining to the Vienna area, back to 1960.

Polycyclic aromatic hydrocarbons in rainwater

A study on polycyclic aromatic hydrocarbons (PAH) in rainwater was carried out over periods of at least one year at two locations in Belgium with different environments. Maximum amounts and concentrations of PAH were reached during the winter period, mainly due to household heating. This influence was also reflected in the relative proportions of the six PAH measured. For comparable periods the amounts of PAH were almost proportional to the quantity of rain. With the available data, and as most of the rainfall is coming from the same wind direction, it was not feasible to localise possible pollution sources based upon the distribution of PAH over the different windsectors, nor was it possible to identify significant differences for both sampling locations due to their different surroundings, indicating that the rain plays an important role in the transport and distribution of pollutants over a wide area. Between about 100 and 170 micrograms m-2 PAH and 2 to 3 g m-2 of total organic carbon content (TOC) per year were deposited by the rain, corresponding to mean concentrations of about 140 ngl-1 of PAH and 2.9 mgl-1 of TOC.

Human rotavirus infection in Malaysia. III. A one year survey on the prevalence of rotavirus enteritis in children

The prevalence of human rotavirus enteritis in children admitted to the gastroenteritis ward of the Kuala Lumpur General Hospital was studied in 1982. Human rotavirus in the stool of the patients was detected by enzyme-linked immunosorbent assay. The survey showed that rotavirus enteritis in children were observed throughout the year, with two broad peaks of rotavirus infection occurring around March and September. The lowest incidence was recorded in July, however, no prolonged period of low prevalence of rotavirus enteritis was observed. The average prevalence for the whole of 1982 was 40% of the total diarrhoeal cases. No significant relationship was noted between the prevalence of the disease and rainfall.

[Leptospirosis on the Island of Reunion. II. Animal leptospiroses]

Bovine leptospirosis is a typical form in the island of Reunion. It appears during the second part of the rain season. The clinical picture of equine leptospirosis is acute hepatonephritis. About 10 serogroups are found in bovines, with greater frequency for Sejroë and Hebdomadis. In horses, the prevailing serogroups are Autumnalis, Ballum, Icterohaemorrhagiae, Australis, Grippotyphosa.

[Leptospirosis on the Island of Reunion. I. Human leptospiroses]

Human leptospiroses in the island of Reunion have a common point: they are severe diseases. Approximately 50 to 60 cases are biologically diagnosed every year. The number of cases is correlated with rainfall. The predominating serogroup is Icterohaemorrhagiae, followed by Canicola, Grippotyphosa and Australis.

Seroepidemiological survey of toxoplasmosis in La Guadeloupe, French West Indies

A random survey of 1% of the total population of La Guadeloupe, French West Indies, for toxoplasmosis was carried out. Blood specimens from 3,238 individuals were collected on filter paper strips and tested for Toxoplasma antibodies by the fluorescent antibody technique. Sixty percent were positive. A gradual increase in positivity with increasing age, and high prevalence in children (50% in the 6- to 10-year age group) were observed. No differences were found among the different ethnic groups, nor among persons in different occupations. Economic status showed a highly negative correlation with antibody prevalence rates. The infection rate was not higher in individuals who consumed raw or undercooked meat, and no differences in antibody prevalence related to the sources of meat were observed. The seropositivity rates varied over a wide range (40-76%) according to the locality; higher Toxoplasma antibody rates were found in areas with higher rainfall, and toxoplasmosis prevalence rates correlated positively with mean annual rainfall but not with altitude or with rural or urban residence. A significant difference was observed between seropositivity rates when people living in houses with or without cats were compared. A higher prevalence of hookworm and Strongyloides infections--considered as evidence of closer contact with moist soil--were found in children with Toxoplasma antibodies than in age-adjusted control children without such antibodies. These results provide evidence that meat plays a negligible role in the transmission of Toxoplasma to man, and support the hypothesis that oocysts shed in cat feces are the almost exclusive mode of human infection in Guadeloupe.

Effects of combinations of simulated acid rain and cadmium or zinc on microbial activity in soil

There was little effect on the rate of CO2 evolution from glucose-supplemented soil, adjusted to pH 3.2 with a 2:1 combination of H2SO4 and fuming HNO3, and concomitant additions of 100 or 1000 ppm Cd or of 1000 or 10,000 ppm Zn (as sulfates) were no more inhibitory than in soil untreated with acid. In soil adjusted to pH 2.8, the lag in CO2 evolution was increased by 1 day, and was extended further by the concomitant addition of 10,000 but not 1000 ppm Zn or of 1000 but not 100 ppm Cd. The growth of Aspergillus niger in soil acidified to pH levels of 3.6 to 4.2 was further reduced by the addition of either 100 or 250 ppm Cd or of 1000 ppm Zn.

An outbreak of waterborne giardiasis associated with heavy water runoff due to warm weather and volcanic ashfall

From mid-June through early August 1980, an outbreak of gastrointestinal illness in Red Lodge, Montana affected approximately 780 persons, as estimated from attack rates of 33 per cent and 15 per cent in urban and rural residents, respectively. Giardia lamblia was identified in stool specimens from 51 per cent of 47 persons with a history of untreated gastrointestinal illness and in 13 per cent of 24 specimens from asymptomatic persons (p = .00045, Fisher's Exact Test). The epidemic curve was bimodal with peaks in mid-June and mid-July. Each peak occurred about three weeks after an episode of very heavy water runoff resulting from warm sunny weather and snow darkened by ashfall from the Mt. St. Helens volcanic eruption of May 18, 1980. Unfiltered and inadequately chlorinated surface water was supplied by the city water system, which was implicated as the vehicle of transmission in the outbreak. Water systems providing unfiltered surface water are more likely to become contaminated during periods of heavy water runoff.

[Relation between meteorological conditions and the atmospheric microflora of the city of Barcelona]

This work deals with a study of the changes observed throughout the four seasons of the year concerning the number of fungi which can be found in the atmosphere of Barcelona. The results obtained will bring us to the conclusion that during the autumn and winter months the number of conidia per m3 is greater than in spring and summer. This observation would confirm the fact that generally speaking in autumn and winter, temperature decreases and humidity increases, while the opposite occurs in spring and summer. These phenomena would be directly related to our findings where we have established that an increase in temperature implies a reduction on the airborne fungi, while the remaining climatic factors taken into account would indicate an increase in the total fungal population. The same relation - phenomena were observed for the strains of the genus Cladosporium, Penicillium, Aureobasidium, Aspergillus and Alternaria, though with some modifications in the three later.