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En Ecuador, el acceso de la poblacion rural a servicios adecuados de atencion secundaria de salud se ha hecho cada vez mas dificil. A pesar de que los sectores publico y privado han acertado en dedicar esfuerzos a la atencion primaria y a la salud publica, la mayoria de las poblaciones rurales no tienen acceso a una adecuada atencion secundaria. Por lo general, los modelos tradicionales de atencion medica secundaria en zonas rurales no se han adaptado a las nuevas situaciones, como la tendencia general a la descentralizacion, el enfasis en el desarrollo de capacidades locales, el antagonismo entre el acceso universal y la autonomia financiera, las alternativas financieras innovadoras y los recien llegados medicos de familia. En 2001, la organizacion no gubernamental con sede en los Estados Unidos de America Andean Health & Development (Saludesa en Ecuador) inauguro un hospital rural de 17 camas, construido conjuntamente con el municipio local y el Ministerio de Salud de Ecuador. El hospital atiende a una comunidad rural de 50000 personas que antes no tenian acceso local a servicios secundarios de salud. Los esfuerzos de AHD/Saludesa para desarrollar una red autosostenible publica/privada de atencion primaria/secundaria de salud y de alta calidad han generado una considerable experiencia en la administracion de un hospital rural. El proyecto piloto de AHD se concentro en un hospital rural y logro su autosostenibilidad total en 2007. Esto se logro mediante una combinacion de mecanismos financieros, entre ellos la venta de paquetes prepagados de atencion sanitaria, un contrato con el Instituto Ecuatoriano de Seguridad Social, contribuciones municipales y el pago tradicional por los servicios.

This investigation examined the cultural context of forest onchocerciasis in several communities in the Dja-Lobo Division of southern Cameroon. The study sought to elucidate behaviors that would enhance or diminish health status relative to forest onchocerciasis and other filarial infections, and to make culturally sensitive and appropriate recommendations regarding the development of health education materials and the long-term sustainability of the ivermectin distribution program in Dja-Lobo. The study consisted of two sequential components; the first was a qualitative study of a few severely affected villages and the second was a quantitative study of 212 randomly selected heads of households from eight villages. The Boulou and Baka peoples in these communities defined general filariasis (minak) as small worms under the skin, identified flies as important transmitters of the illness, and indicated that blindness and other skin and ocular problems were a consequence of the illness. Illness of the Dja (referring to an illness found near the Dja River) was another illness that was closely linked to onchocerciasis; local people indicated it was transmitted by the black flies found near the Dja River, resulting in severe itching and leopard skin. These and other cultural-behavioral data on filariasis were used to implement a health education and distribution program.The cultural context of forest onchocerciasis was studied in the Boulou and Baka ethnic communities in the Dja-Lobo Division of southern Cameroon. A 2-day survey used focus group interviews followed by a questionnaire administered to 212 randomly selected individuals in 8 communities (88 male and 124 females heads of household) to assess their knowledge about onchocerciasis. Most people (98%) had some knowledge about the disease. Minak was the term used for filariasis by most people (97%) and people knew (90%) that black fly (nyamendimi) was responsible for its transmission. Other vectors of the illness identified were mosquitoes, dirty water, sorcery, and taboo foods. 81% thought that maternal transmission was possible and 66% indicated that filariasis could be transmitted sexually. Virtually all respondents associated itching and rash with minak (filariasis) and more than 60% also recognized the swelling of the skin and leopard skin as manifestations of filariasis. Filariasis, malaria, worms, and blindness were placed in the middle category when the severity of various diseases was ranked by 20 Boulou adults. In contrast, the Baka did not think that filariasis caused blindness, nor that it is linked to eye-worms. However, the 212 individuals ranked blindness as the most severe among other diseases (filaria, malaria, diarrhea, and intestinal worms). 80% of the Boulou and Baka adults had had filariasis in the previous year, but only 5% of the Boulou children and none of the Baka children had had filariasis during that time period. With respect to intestinal worms, 71% of the Boulou adults and 60% of the Baka adults had had intestinal worms in the previous year, while more than 90% of the Boulou children and all of the Baka children had had intestinal worms. Of the 90% who revealed that they had had filariasis at least once before, 69% sought treatment. 54% had tried traditional treatment, while 50% had tried Notezine, 49% had tried Phenergan, and 38% had tried M.G. Lumiere.

With few exceptions, efforts to control schistosomiasis have relied upon ongoing community cooperation with ‘outsiders’ rather than creating within the community the capacity and means for carrying out ongoing disease control measures with minimal external support. Offered as a useful model is a program in Kaele subdivision, Extreme North Province, Cameroon designed to establish and integrate within the primary health care (PHC) system the control of urinary schistosomiasis, hyperendemic in the region. At the community level, and with minimal dependence upon external resources, culturally appropriate and effective health education was instituted, the capacity to diagnose and treat schistosomiasis was created, diagnosis and drug therapy (praziquantel) was made available conveniently and at low cost, and, on a very limited basis, snails were controlled. Efforts were made to build upon and strengthen existing community structures and institutions rather than create new ones. The impact of the interventions was measured in terms of changes in knowledge and behavior, prevalence and intensity of infection, utilization of health services, and the ability to finance the control activities within the context of a generalized cost recovery system. Program successes and failures are discussed, as well as lessons learned and their implications.

Use of the fluorescence-activated cell sorter proved to be an accurate and highly efficient means for cloning Babesia parasites. These qualities were examined by separating a mixed population of Babesia-infected bovine erythrocytes composed of two isolates with different karyotypes. Direct evidence of polymorphism was detected during comparison of the resultant clones.

One of the central challenges facing modern neuroscience is to explain the ability of the nervous system to coherently integrate information across distinct functional modules in the absence of a central executive. To this end Tononi et al. [Proc. Nat. Acad. Sci. USA 91, 5033 (1994)] proposed a measure of neural complexity that purports to capture this property based on mutual information between complementary subsets of a system. Neural complexity, so defined, is one of a family of information theoretic metrics developed to measure the balance between the segregation and integration of a system's dynamics. One key question arising for such measures involves understanding how they are influenced by network topology. Sporns et al. [Cereb. Cortex 10, 127 (2000)] employed numerical models in order to determine the dependence of neural complexity on the topological features of a network. However, a complete picture has yet to be established. While De Lucia et al. [Phys. Rev. E 71, 016114 (2005)] made the first attempts at an analytical account of this relationship, their work utilized a formulation of neural complexity that, we argue, did not reflect the intuitions of the original work. In this paper we start by describing weighted connection matrices formed by applying a random continuous weight distribution to binary adjacency matrices. This allows us to derive an approximation for neural complexity in terms of the moments of the weight distribution and elementary graph motifs. In particular we explicitly establish a dependency of neural complexity on cyclic graph motifs., Comment: submitted Phys. Rev. E, Nov. 2010

Epidemiologists: Aerial Photography and Other Remote Sensing Techniques” (Cline, 1970) in the American Journal of Epidemiology little could I imagine that 20 years later the first International Conference on Applications of Remote Sensing to Epidemiology and Parasitology would be held (Louisiana State University, Baton Rouge, June 67, 1990), nor that Geospatial Health would make its debut in 2006. When I wrote this paper, my first, I was a doctoral student in epidemiology at the University of California, Berkeley. The great arbovirologist/epidemiologist William C. Reeves was my faculty mentor, overseeing my research on the distribution in humans of neutralizing antibodies to vesicular stomatitis virus in Central America and Panama (Cline, 1973, 1976). Over 50% of the human population had serologic evidence of past infection, yet the means of transmission was unknown. Among possible determinants of transmission I wanted to classify the ecological characteristics of the hundreds of study communities, but these data were only available in very crude form. Hoping that aerial photographs of the communities would offer a more precise means of ecological classification, I enrolled in the course “Aerial Photo Interpretation” offered by the University of California’s Department of Geography and taught by Robert N. Colwell, a leading authority on remote sensing of natural resources. I recall my fascination in learning from Professor Colwell about the wide range of remarkable applications of remote sensing in agriculture, forestry, hydrology, oceanography, range and wildlife management, geography and cartography. A dramatic example, I learned that early disease and stress in trees and other crops could be detected remotely before evidence was apparent from ground level inspection! From my epidemiology studies I was beginning to appreciate that while most pathogens transmitted in a human-to-human cycle are not constrained geographically, zoonotic and insect-transmitted diseases, in contrast, tend to be focal in distribution, with their maintenance cycles dependent upon exacting ecological conditions. The term “landscape epidemiology”, coined by the Soviet Academician E.N. Pavlovsky (1884-1965), provided the spark which led me to link remote sensing with epidemiology, and to begin speculating about how epidemiology might be added to the list of disciplines for which remote sensing provided a powerful tool for investigation and disease control. Pavlovsky and his colleagues developed the concept of “disease nidality”, i.e. that certain diseases such as old world leishmaniasis and tick-borne encephalidities, occupy ecological niches much in the same manner as any living thing has a characteristic niche in nature (Pavlovsky, 1966). Russian Spring and Summer Encephalitis (RSSE), associated with the taiga forests of Siberia, is another example. This concept was expanded by Western investigators such as Ralph Audy at the University of California, San Francisco, who applied it to the Corresponding author: Barnett L. Cline Professor Emeritus, Tulane University Current address: P.O. Box 1477 Blanco, Texas 78606, USA E-mail: blchome@moment.net Invited editorial for the inaugural issue of Geospatial Health

The status of schistosomiasis in Cameroon was examined in a nationwide survey of 5th grade schoolchildren. Five hundred twelve schools were surveyed; 19,524 urine and 22,166 stool samples were examined. The 3 northern provinces, which comprised 29% of the population, had 87% of all urinary and 82% of all intestinal cases. These provinces have a low seasonal rainfall. The presence of temporary bodies of water and of molluscan intermediate hosts adapted to this environment permits intense transmission of schistosomiasis haematobium and mansoni. In the rest of the country, the distribution of Schistosoma haematobium and S. mansoni was highly focal. S. intercalatum endemic areas were restricted to the equatorial forest and were small with low prevalences and intensities.

To investigate the usage of antischistosomal drugs in the Nile Delta, an antischistosomal drug history was obtained by interview from a sample of inhabitants of the villages of Halaba (1,024, or every 4th household) and Kharkania (505, or every 20th household), south-central Nile Delta. Only 3% and 0.4% of participants, respectively, in the 2 villages reported receiving antischistosomal drugs during the previous 4 years. Most villagers received oral compounds (praziquantel and niridazole), and the treatment regimen was completed by 95%. This study reveals changes in antischistosomal drug usage since a study 8 years earlier in the village of Halaba, when most of the drugs were injectable compounds.

PCR-based DNA typing of biological evidence is now widely used in forensic analyses due to the obvious advantages of enhanced sensitivity, the ability to distinguish discrete alleles and efficacy with degraded samples. A multiplex short tandem repeat (STR) system has been previously developed which successfully co-amplifies six STR loci HUMTH01, D21S11, D18S51, D8S1179, HUMVWF31/A and HUMFIBRA (FGA) in conjunction with the X-Y homologous gene Amelogenin. This is known as the second generation multiplex system (SGM). Detection of the PCR products is undertaken on ABD 373A or 377 automated sequencers using denaturing polyacrylamide gels coupled with fluorescent-based technology. We have evaluated this system for routine forensic use and demonstrated that the technique is robust and reproducible under conditions consistent with those encountered in a forensic environment. A total of 132 stains from simulated and actual casework were analysed, together with relevant control areas and reference samples. The success rate was high with 76% of stains giving full profiles; we were also able to successfully detect and interpret mixtures. No mistyping was observed. A detailed examination of each of these profiles has assisted in the development of guidelines for casework interpretation. Although artefacts, stutter peaks and undenatured DNA were occasionally observed, these did not interfere with the accuracy of interpretation. In addition 38 samples, previously examined using the quadruplex system, were analysed with the SGM to enable a direct comparison to be made between the systems. The performance of the system with poor quality samples demonstrated its use as a rapid and powerful technique for individual identification.

Potential diagnostic indicators of onchocerciasis (subcutaneous nodules, depigmentation or leopard skin, microfilaruria, diethylcarbamazine patch test positivity, excoriations, and pruritus) were evaluated in a rain forest region of southern Cameroon for usefulness in rapid assessment of onchocerciasis endemicity in communities. Thirty-two study villages were selected, representing high, intermediate, and low prevalence levels, and 846 adult male residents of these communities 20 or more years of age were examined according to a defined protocol. Skin snips (from each iliac crest) served as the reference standard. Skin snip positivity was 75.5%; the effect of age was minimal. Leopard skin and nodules showed the strongest correlation with both the skin snip prevalence and community microfilarial load, as reflected by the adult male study population. We selected > or = 20% nodules or > or = 20% leopard skin as the most appropriate local criteria for assigning a community to high priority for control, which corresponds to a > or = 90% skin snip prevalence in adult males. While this criteria should not be applied to regions with savannah onchocerciasis, we believe the methodology can and should be used to determine appropriate diagnostic indicators for rapid assessment of Onchocerca volvulus endemicity in regions with different dynamics of transmission and clinical expression of disease.

Carrying out the obligatory ritual of reading the addresses of my predecessors I learned that the Society had met once previously in Cincinnati, in 1945, before the “and Hygiene” was added to our name. Appropriately, President Rolla Dyer's address that year was titled “Medical Research in the Postwar World”, and it contained hints of things to come. For example, Dyer mentioned that to promote the training of scientists the National Institute of Health (NIH) had established fellowships, some of which had been filled! I am pleased that the venue of this meeting is Cincinnati, a city which at a personal level has much meaning for me. It is my mother's birthplace, and is where my parents met and married before they migrated to that then-distant land, Texas. One memorable summer my brother and I stayed with a much-loved uncle and aunt in Cincinnati who were devoted fans of the Cincinnati Reds, and they took us often to the ballpark.

A national survey of Ascaris lumbricoides and Trichuris trichuria was carried out in Cameroon on more than 22,000 children from a random sample of 512 schools. Prevalence rates of both A. lumbricoides and T. trichuria infection were very low in the tropical zone (below 5%). They increased markedly in the equatorial zone, Guinea-type climate, to 60-85% for A. lumbricoides and 85-95% for T. trichuria. In the equatorial zone with Cameroon-type climate, prevalences were slightly lower: 50-70% for A. lumbricoides and 70-90% for T. trichuria infections. Environmental conditions are the main factors explaining these differences. Other factors (altitude, population density and urbanization) were not important. The entire population of villages selected from distinct climatic zones of Cameroon were also examined. The age group distribution of A. lumbricoides and T. trichuria infections indicated acquisition early in life, reaching a peak in early childhood, followed by a stable prevalence rate.

Tropical Diseases Readers of this review, mostly American physicians, will want to know the merits of this distinctly British product. Since 1898, when Patrick Manson (widely recognized as the "father of tropical medicine" in the English-speaking world) produced the first edition ofManson's Tropical Diseases, the discipline of tropical medicine has changed. It has evolved from its colonial origins to a presentday focus on treating and controlling the major diseases, largely infectious, found predominantly in tropical and developing countries. Although initially concerned with preserving the health of civil servants, merchants, military, clerics, and selected populations of indigenous workers, the discipline of tropical medicine now finds itself with new and broader challenges. It faces a world shrunken drastically by jet travel, with newly emerging and reemerging infectious diseases. It faces new patterns of disease influenced by powerful interrelated global factors, such as rapid urbanization, aging populations, economic stagnation, environmental degradation, and

The intradermal reaction with Schistosoma mansoni adult-worm antigen (35-40 microgram/ml nitrogen) was evaluated as an edpidemiologic tool in an endemic Puerto Rican community where the prevalence of S. mansoni infection was 36% and the geometric-mean egg count was 17.6 eggs/g. Subcutaneous injections of antigen were made in forearms, and stool specimens were examined for S. mansoni eggs by a formol-ether concentration method. Of 296 persons tested, 43% had positive intradermal reactions (greater than or equal to 1.0 cm 2 at least twice the area of the control wheal), compared to 48% positive stool examinations. However, sensitivity was low at 36% for children 14 yr old or less, and only 73% to 79% for adults. The test results were very specific for children (96%), but 32% of stool negative adults were positive. Mean wheal area was not directly related to intensity of infection as determined by egg counts in either children or adults, but did increase directly with age. Mean wheal areas were greater for males than females (both children and adults) at all intensities of infection. Because of unsatisfactory sensitivity and specificity the intradermal test may overestimate the prevalence of infection when rates are low, and underestimate prevalence of infection when rates are high. For its proper interpretation, complementary parasitologic data from stool surveys are required.

The principal objective of this study was to determine ecological associations of vesicular stomatitis virus (VSV)- New Jersey and VSV-Indiana in rural Central America and Panama. Two types of information were linked: the results of neutralizing antibody tests performed on sera from 3,232 lifetime residents of 189 rural study communitities of Central America and Panama, and ecological characteristics of the study communities as determined from natural resource atlases. The major finding was that neutralizing antibody acquistion to VSV-New Jersey was greatest for persons living at elevations between 350 and 649 meters, with relatively open, dry vegetation and distinct seasonal alternation of dry and moist (not wet) ground conditions. Similar ecological associations were found for VSV-Indiana, except that the risk of infection was also high in moist environments with dense tree cover. The results suggest that VSV-New Jersey and VSV-Indiana have similar but not identical maintenance and transmission cycles and that basic maintenance cycles for both viruses may exist in dry, open habitats rather than in tropicla rain forest habitats as was previously assumed for VSV-Indiana.

This is a report of a case of massive cutaneous larva migrans in a 20-year-old man who also had pulmonary symptoms and larval invasion of the skeletal muscles. In sections of a muscle biopsy specimen taken 3 months after the initial cutaneous lesions, a third-stage Ancylostoma larva, probably A. caninum, was found within a muscle fiber.

The circumoval precipitin (COP) test was used to detect serum antibodies to Schistosoma mansoni, S. haematobium, or both species by using eggs of either species of schistosome. Eggs of either species were adequate as antigens but, in general, the sera of S. mansoni-infected individuals caused more circumoval precipitates for form around S. mansoni eggs (higher reactivity) than did the sera of S. haematobium-infected individuals. However, sera from individuals with either or double infections reacted equally with S. haematobium eggs. In addition, more circumoval precipitates were formed around S. haematobium eggs obtained from human urine than around S. mansoni eggs obtained from mouse livers. We demonstrate that human infection with either species of schistosome can be diagnosed by the COP test, but that identification of the schistosome species involved in the infection is not possible with this test. In addition, by eliminating the need for maintaining a schistosome life cycle in the laboratory the demonstration of the high reactivity of S. haematobium eggs from urine greatly simplifes the performance of the COP test in areas where S. haematobium-infected individuals can be found and will cooperate by providing urine. We also obtained serum specimens by venipuncture, and capillary blood dried on filter paper, from Egyptians infected with S. mansoni, S. haematobium, or with both species of schistosome. Serum eluted from the filter paper was then compared with serum from venipunctures with respect to their reactivity in the COP test done with fresh S. haematobium eggs as antigen. Serum eluates from freshly dried blood were significantly less reactive than serum obtained by venipuncture in terms of positive reactions and characteristics of the COP precipitate. Storage of the filter paper blood at 4°C for 6–12 months resulted in an even greater reduction of reactivity. Thus, for the COP test serum obtained by venipuncture is preferable to serum eluates obtained from blood on filter paper for the serodiagnosis of infection with S. mansoni and S. haematobium.

To further investigate factors responsible for the recently documented changes in schistosomiasis patterns in the Nile Delta, questionnaire-derived information on antischistosomal drug usage was obtained from a 25% systematic sample of 609 residents of a stable village in the south-central Delta. Ten percent of the population had received antischistosomal drugs during the previous 4 years. Most of the drugs administered were injectable compounds, and 92% of individuals receiving them failed to complete the treatment regimen. Additional sources of information from a village physician, a pharmacist and a major pharmaceutical corporation confirmed and expanded the survey findings, indicating that antischistosomal drug usage cannot explain the recently observed changing patterns of human schistosome infections in the Nile Delta region.

To determine whether the sharply declining Schistosoma haematobium infection rates in parts of the Nile Delta could be generalized to the entire region, and to update the status of S. mansoni infection rates, a large scale survey was undertaken in 1983 in 70 of the 71 districts of the Nile Delta. In a house-to-house survey, > 91% of the sample population of 16,675 participated by providing stool and/or urine specimens which were examined qualitatively by Kato thick smear and sedimentation techniques, respectively. After the 1935 survey by Scott, the prevalence of S. mansoni appeared to change little, from 33% in 1935 to 39% in 1983, but a more sensitive diagnostic technique in 1983 strongly suggested that the actual prevalence had decreased between the 2 surveys. In contrast, the prevalence of S. haematobium infection decreased from 56% to 5%, with a similar decline in all 8 governorates. The dramatic decline in S. haematobium prevalence has been accompanied temporally with a sharp decrease in the population density of Bulinus truncatus. S. mansoni has become the predominant human schistosome species in the Nile Delta.

The Boqueron Schistosomiasis Project is a prospective community-based study of Schistosoma mansoni infection after the interruption of transmission by nonchemotherapeutic control measures. The study methods and the parasitologic results of the first five annual stool surveys are described in this report. In the first year, 1972, among 904 inhabitants (88% of the total population) the prevalence of infection was 40%, and the geometric mean intensity of infection among positives was 16.1 eggs per gram (epg). Snail control was begun in early 1973 with molluscicides and habitat modification. Intensive monitoring every 2 weeks revealed only 63 noninfected Biomphalaria glabrata in the community during the subsequent 4 years. The incidence of new infectins among people negative in all previous surveys dropped from 17% in 1972 to 1% in 1974 and has remained negligible since then. Among young children and newborn, only four new infections (all less than 5 epg) were found after the first control year. Despite this low rate of transmission, prevalence only decreased from 37% to 34%, and the population geometric mean fecal egg output has not substantially changed in a cohort of 528 individuals examined in each of the six annual surveys. Possible reasons for the minimal change in parasitologic status are discussed and include water contact behavior outside the community and changes in laboratory techniques. Data from the first 5 years of the study suggest that in a population where mean intensity of infection with S. mansoni is low, further decreases in prevalence and intensity of infection occur slowly. The implications for control programs based on nonchemotherapeutic measures are discussed.

The low Schistosoma mansoni egg counts generally found in Puerto Rico require a sensitive technique for epidemiologic studies. The Ritchie formol-ether concentration technique has been modified to make it more useful for this purpose. The modified technique was compared with the older technique by analyzing fecal specimens from ten individuals with varying levels of infection. It was also compared with the Kato thick-smear technique with specimens from 25 other patients. In both series, three replicates of each technique were done on each stool. Results indicated that the modified technique was more sensitive than the older technique in terms of number of eggs counted, and that the sediment was smaller and clearer and required about 15% less time to examine. In comparison with the Kato technique, it was more successful in detecting light infections, although at higher levels of intensity, when expressed on an eggs-per-gram basis, the thick smear detected relatively more eggs. For the series as a whole, coefficients of variation for the three replicates done on each stool were smaller for the modified concentration technique than for the Kato technique. This is interpreted to reflect satisfactory reproducibility of the concentration technique when compared to the Kato technique. The concentration technique has the additional advantages over the thick smear of detecting other intestinal parasites and allowing for transportation and storage after feces are preserved in formalin.

During the 1975 dengue epidemic in Puerto Rico, we studied three patients who had serologically confirmed dengue with hemorrhagic manifestations. None of the patients went into shock and none died. Only one of the patients had disease that resembled dengue hemorrhagic fever (DHF) as observed in Southeast Asia. This patient was a 14-year-old boy who had epistaxis, a positive tourniquet test, moderate thrombocytopenia, and significant hemoconcentration. The other two patients had hemorrhagic disease which was of clinical importance, but was not typical of DHF. These cases of dengue with hemorrhagic manifestations are the only ones known to have been documented in Puerto Rico.

This study evaluated the efficacy and tolerance of a single oral 400-mg dose of albendazole on Necator americanus larvae, and compared its efficacy when administered between meals or with a meal. Twenty-nine healthy and hookworm-free male volunteers were exposed on the forearm to approximately 45 8-day-old N. americanus larvae. All subjects developed discrete maculopapular eruptions at the site of larval application. Following a random double-blind study design, each subject received at the end of the 6th post-infection day either the investigational drug or a placebo as follows: Group I (n = 8)-placebo; Group II (n = 11)-400 mg albendazole with a meal; Group III (n = 10)-400 mg albendazole 3 or more hours after or before a meal. On day 56 post-infection, the stools of all subjects who received placebo were positive for N. americanus eggs (by zinc sulfate flotation technique), compared with 48% positivity (10/21) in those who received albendazole (P = 0.01). By day 63 post-infection, an additional three subjects in the treatment group became positive, for an overall 62% rate of positivity (13/21), i.e., albendazole prevented patent infection in 38%. Administration of albendazole with a meal did not alter drug efficacy. In those subjects in whom patent infections were not prevented, egg output was one-fourth that of the placebo group. There was no difference in viability of eggs appearing in feces of treated and untreated subjects as judged by larval development in Harada-Mori cultures. Our data indicate that albendazole is active against pre-intestinal stages of N. americanus in human infections.

The objective of this study was to determine a suitable method for quantitating Schistosoma haematobium eggs in urine specimens preserved in carbolfuchsin. Using a 0.002% carbolfuchsin-phenol-alcohol solution as a stain/preservative for urine obtained from 30 patients infected with S. haematobium, we compared egg counts obtained with four quantitative techniques: Nytrel filtration, Nuclepore filtration, suction filtration and centrifugation. Centrifugation gave statistically higher values than all other techniques for absolute number of eggs recovered in the preserved urine. We also measure a statistical difference between the counts obtained from Nuclepore filtration of fresh urine and those established on an equivalent volume of preserved urine by Nuclepore and Nytrel filtration. The preserved urine frequently caused obstruction of both Nuclepore filters and Whatman No. 1 filters (used in suction filtration), rendering them technically difficult to use and less satisfactory than other methods. From the techniques we examined, we conclude that in field studies where preservation of urine is necessary, preparation of Nuclepore filters with fresh urine, or centrifugation of a carbolfuchsin-preserved urine, are the methods of choice for quantitation of specimens.

Epidemics of dengue fever occurring in Puerto Rico in 1963 to 1964 and 1969 were caused by dengue-3 and dengue-2 (DN-2) viruses, respectively, but endemic dengue transmission has never been documented on the Island. Since the 1969 epidemic, a surveillance system has detected DN-2 activity on the Island during each of the years 1970 through 1973, which suggests endemic persistence of the virus. This report describes the investigation of localized outbreaks of DN-2 in Guanica-Ensenada (1972) and Villalba (1973), and presents epidemiological, serological, and virological data from the outbreaks. Analysis of geographic distribution of dengue activity in Puerto Rico in recent years indicates that the DN-2 transmission in 1970 to 1973 may represent a long tail-off of the 1969 epidemic rather than the emergence of a truly endemic situation.

(1937). The Influence of Smell on Reaction Time. The Journal of General Psychology: Vol. 16, No. 1, pp. 279-282.

In order to understand adequately the dynamics of vector-borne disease, one must understand how and why vector populations change over time. We describe a long-term, cooperative study of seasonal fluctuation in populations of the Aedes aegypti mosquito in Puerto Rico. During each month of the first 3 years of the project, A. aegypti was found breeding in all five communities studied. Mosquito density was positively correlated with rainfall, the relationship being more marked in the dry, south-coastal part of the island. Discarded tires and animal watering pans were the two most common larval breeding sites. In general, houses in Puerto Rico harbor more potential A. aegypti breeding sites than those in other tropical locations, probably because Puerto Rico is relatively more affluent.

A population-based approach was used to investigate morbidity from Schistosoma mansoni in a rural community in eastern Puerto Rico that was representative of remaining endemic foci on the island. In 1974 the prevalence of infection 855 of 1,056 inhabitants was 32.7% and the geometric mean egg output was 17.6 eggs per gram. A standardized medical history was obtained, and physical and laboratory examinations were performed on 737 (70%) of the community residents. Quantitative S. mansoni egg counts were performed on 1 gram of feces with a modified Ritchie formol-ether concentration technique; other intestinal parasites were recorded on a semi-quantitative basis. Interviews and physical examinations were conducted "blind" to minimize observer bias, and statistical analysis was done on data from 149 infected subjects and 149 noninfected controls matched by age and sex. For subjects under 20 years of age the frequency of hookworm infection and trichuriasis and absolute eosinophilia was significantly higher in the infected group, but no difference was found in the frequency of signs and symptoms of schistosomiasis. For the subjects 20 years and over, the symptom "blood in the stool" was reported more frequently in the infected group, but hematocrit level did not differ between infected and noninfected controls. Although palpable livers were noted more frequently in infected (8) than in noninfected (1) subjects 20 years and over, further evaluation of these subjects cast doubt upon a causal role for S. mansoni. These data indicate that morbidity from S. mansoni infection in the community is low, a finding consistent with the apparent decline in S. mansoni morbidity in Puerto Rico during recent decades and the relatively low intensity of infection in this community. Nevertheless, because of the sporadic occurrence of S. mansoni-induced disease on the island, and because heavily infected subjects are clearly at greater risk of disease, we are recommending treatment for community residents with high egg output.

We utilized the circumoval precipitin (COP) test, Ouchterlony immunodiffusion, and the enzyme-linked immunosorbent assay (ELISA) for the serodiagnosis of human infection with Schistosoma mansoni or S. haematobium, or with both species of schistosome. Only the COP test correctly identified all of those with schistosome infection, although differentiation as to schistosome species was impossible. Circumoval precipitates around S. haematobium eggs from human urine were more numerous and larger than those around S. mansoni eggs obtained from mouse livers. Ouchterlony immunodiffusion with S. mansoni or S. haematobium worm extract failed to diagnose correctly approximately one of every five infected individuals. Mean absorption values of the S. mansoni soluble egg antigen (SEA) used in the ELISA were similar in serum samples from persons infected with either or both species of blood flukes. This suggests that S. mansoni SEA is not species-specific. The ELISA correctly identified, however, 30 of 32 infected individuals, indicating high sensitivity.

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