Effect of tourism and trade on intestinal parasitic infections in Guatemala.

A survey was performed to determine if infection with gastrointestinal parasites differs between the rural and urban poor inhabitants of Guatemala. A total of 317 stool samples from children in two towns, one rural and one urban, were examined using the formalin-ether concentration method. The overall prevalence of parasites in infected children was 67%, 20%, 30%, and 22%, respectively for Ascaris lumbricoides, Trichuris trichiura, Giardia duodenalis and Entamoeba histolytica in the rural town of La Mano de Leon and 49%, 14%, 15%, and 21%, respectively in the urban town of Santa Maria de Jesus. Two sub-studies were carried out to determine the effects of (1) gender and (2) age on the rate of parasitic infections. Female children in the 1-to 6-year-olds age group in Santa Maria de Jesus had more infections with A. lumbricoides and T. trichiura when compared to La Mano de Leon. A. lumbricoides was most prevalent in Santa Maria de Jesus. These results propose that accessibility to tourism and trade decreases the risk for the establishment of parasitic diseases in children of Guatemala possibly due to improvements in basic nutrition and availability of health care.

A study of risk factors associated with the prevalence of Cryptosporidium in villages around Lake Atitlan, Guatemala.

Cryptosporidium parvum is an endemic, zoonotic coccidian parasitosis that is highly prevalent in third-world countries where waterborne fecal contamination of food and drink or person-to-person contact with oocysts are the most common methods of transmission of the enteric protozoan. This type of transmission of the parasite made the villages around Lake Atitlan, Guatemala a unique site to compare environmental risk factors with the level of Cryptosporidium infections in the local residents. The study was carried out in two villages, San Antonio Palopo and Santa Catarina Palopo, located in the highlands above the shores of the lake. Smears from stool specimens of patients with gastroenteritis were processed using Kinyoun's modified acid-fast stain and observed with light microscopy. Of the 100 residents examined from the two villages, 32% had Cryptosporidium infections. Female children had the highest prevalence of infection (44% in San Antonio Palopo and 46% in Santa Catarina Palopo, p<0.05), and they also had significantly higher infection rates than males, 50% vs. 17%, respectively. The prevalence rate was not influenced by the season of the year or by the location of the residents. We found differences in prevalence rates due to age and gender, and we suggest that the high infection rates of specific groups are associated with their exposure to the contaminated water supply from Lake Atitlan.

A study of risk factors associated with the prevalence of Cryptosporidium in villages around Lake Atitlan, Guatemala

Cryptosporidium parvum is an endemic, zoonotic coccidian parasitosis that is highly prevalent in third-world countries where waterborne fecal contamination of food and drink or person-to-person contact with oocysts are the most common methods of transmission of the enteric protozoan. This type of transmission of the parasite made the villages around Lake Atitlan, Guatemala a unique site to compare environmental risk factors with the level of Cryptosporidium infections in the local residents. The study was carried out in two villages, San Antonio Palopo and Santa Catarina Palopo, located in the highlands above the shores of the lake. Smears from stool specimens of patients with gastroenteritis were processed using Kinyoun's modified acid-fast stain and observed with light microscopy. Of the 100 residents examined from the two villages, 32 percent had Cryptosporidium infections. Female children had the highest prevalence of infection (44 percent in San Antonio Palopo and 46 percent in Santa Catarina Palopo, p<0.05), and they also had significantly higher infection rates than males, 50 percent vs. 17 percent, respectively. The prevalence rate was not influenced by the season of the year or by the location of the residents. We found differences in prevalence rates due to age and gender, and we suggest that the high infection rates of specific groups are associated with their exposure to the contaminated water supply from Lake Atitlan.

Identification of Anopheles aquasalis as a possible vector of malaria in Guyana, South America

Adult female mosquitoes were collected in Mahdia, Guyana, to determine the incidence of malaria in Anopheles species found during the month of June 2000. Centers for Disease Control miniature white (incandescent) light traps, model 512, and miniature black (ultraviolet) light traps, model 912, were used to capture female mosquitoes. Numbers of mosquitoes collected were compared between white and black light traps and between traps set outside and inside of buildings. Adult female Anopheles mosquitoes were identified and an ELISA dipstick test for Plasmodium vivax and Plasmodium falciparum was performed on each mosquito. An aquasalis, An oswaldoi, and An braziliensis were attracted to white light traps. An triannulatus and An darlingi were collected from black light traps. Approximately the same numbers of all female Anopheles mosquitoes 28/45 (62) were caught inside buildings as outside. Numbers of female non-anopheles mosquitoes captured in light traps varied between the traps set outside of buildings and inside of buildings with bright light traps collecting 91/122 (75). A total of 45 Anopheles mosquitoes were captured and 122 non-anopheles species. Of the two known vectors of malaria in Guyana, An darlingi mosquitoes were not infected with P vivax but An aquasalis was found to be a carrier. The findings of this study suggest a need for further surveying and identification of current malaria vectors in Guyana.

Identification of Anopheles aquasalis as a possible vector of malaria in Guyana, South America.

Adult female mosquitoes were collected in Mahdia, Guyana, to determine the incidence of malaria in Anopheles species found during the month of June 2000. Centers for Disease Control miniature white (incandescent) light traps, model 512, and miniature black (ultraviolet) light traps, model 912, were used to capture female mosquitoes. Numbers of mosquitoes collected were compared between white and black light traps and between traps set outside and inside of buildings. Adult female Anopheles mosquitoes were identified and an ELISA dipstick test for Plasmodium vivax and Plasmodium falciparum was performed on each mosquito. An aquasalis, An oswaldoi, and An braziliensis were attracted to white light traps. An triannulatus and An darlingi were collected from black light traps. Approximately the same numbers of all female Anopheles mosquitoes 28/45 (62%) were caught inside buildings as outside. Numbers of female non-anopheles mosquitoes captured in light traps varied between the traps set outside of buildings and inside of buildings with bright light traps collecting 91/122 (75%). A total of 45 Anopheles mosquitoes were captured and 122 non-anopheles species. Of the two known vectors of malaria in Guyana, An darlingi mosquitoes were not infected with P vivax but An aquasalis was found to be a carrier. The findings of this study suggest a need for further surveying and identification of current malaria vectors in Guyana.

The effects of chronic exercise on metabolic and reproductive functions in male rats.

Previous studies concerning the effects of swimming on various endocrine gland functions have been performed. Our study was thus designed to analyze the effects of chronic exercise (swimming) on the resting metabolic rates (RMR) of adult rats. Most of the protocols used a water temperature of 33 C. It is our contention that such a protocol is not exclusively an exercise stress, but also a hypothermic stress. The protocol of our study was designed in a way that hypothermic stress was not part of the exercise stress. Male rats were swam in 36 C water for 3 hours a day, 5 days a week for 4 months. RMR of the animals were determined 24 h after the next to last swim session. Plasma hormone levels and epididymal sperm concentrations were determined in animals sacrificed 24 h after the last swim period. Exercising animals had a RMR 16% greater than that of control animals (p < 0.02), yet total and free thyroxine and total and free triiodothyronine were not significantly elevated. Neither plasma testosterone nor epididymal sperm counts were significantly reduced in the exercising animals. It appears that chronic exercise produces an elevation in RMR which is unrelated to thyroid gland activity and does not suppress the hypothalamic-pituitary-gonadal axis.

Stimulation of leukocyte lysophospholipase activity by noninfectious agents.

Mouse peritoneal leukocyte lysophospholipase (LPL) activity was studied to determine whether or not noninfectious agents cause increased enzyme activity and whether neutrophils have LPL activity. In the first study, mice infected with Ascaris suum, a known inducer of LPL activity, were given intraperitoneal injections of proteose peptone, thioglycolate, bovine albumin, paraffin, glycogen, or A. suum whole worm extract (WWE). Cell populations collected from mice injected with A. suum WWE, proteose peptone, thioglycolate, or bovine albumin contained increased numbers of neutrophils and eosinophils. These cell populations had increased LPL activity when treated, in vitro, with either A. suum WWE, zymosan-activated complement, or with the agent they were induced with. However, the LPL activity of the different cell populations did not respond to all treatments in the same way. In a second study, A. suum-infected or noninfected mice were given intraperitoneal injections of paraffin, thioglycolate, glycogen, or A. suum WWE. Enriched cell populations containing either lymphocytes or macrophages, from infected or noninfected mice, did not have increased LPL activity following in vitro stimulation with A. suum WWE, zymosan-activated complement, or with the agent they were induced with. Enriched neutrophil populations from infected or noninfected mice had increased LPL activity following in vitro treatment with A. suum WWE or zymosan-activated complement. Results demonstrate that the LPL activity of peritoneal leukocytes can be induced by noninfectious agents and that neutrophils have increased LPL activity following in vitro stimulation.

In vitro damaging effect of leukocytes, serum, and peritoneal fluid on Ascaris suum infective larvae.

Peritoneal leukocytes, serum, and peritoneal fluid from Ascaris suum-infected or noninfected mice were studied using 51Cr release and larval mobility to determine if they had in vitro cytotoxicity for A. suum infective larvae. Mouse serum or peritoneal fluid from infected and non-infected mice was added to leukocyte-larvae cultures to determine their effect on leukocyte damage to larvae. Leukocytes from A. suum infected mice were cytotoxic for A. suum larvae in the presence of serum from infected or noninfected mice but only serum from infected mice produced larval cytotoxicity independent of leukocytes or in the presence of leukocytes from noninfected mice. Mouse peritoneal fluid from infected or noninfected mice was found to damage larvae independent of leucocytes. Cytotoxic activity was blocked when serum or peritoneal fluid was heat-inactivated suggesting complement as the damaging agent.

Lysophospholipase activity of Ascaris suum-induced mouse peritoneal neutrophils and eosinophils.

Lysophospholipase activity of mouse peritoneal neutrophils and eosinophils was studied to determine if neutrophils and eosinophils have lysophospholipase activity when treated with Ascaris suum whole worm extract, if zymosan activated complement can induce increased lysophospholipase activity, or if the immune status of the host has an effect on lysophospholipase activity. Neutrophils from noninfected or infected (immunized) mice were found to have increased lysophospholipase activity when treated with A. suum whole worm extract or zymosan activated complement demonstrating neutrophils as a source of lysophospholipase activity in the presence or absence of an immune response. Eosinophils from immunized mice had increased lysophospholipase activity when treated with either A. suum whole worm extract or zymosan activated complement.

Evaluation of Army field sanitation during Blazing Trails '87.

US medical personnel serving in Ecuador analyzed how the field sanitation procedures of troops employed in Blazing Trails '87 had impact on living conditions and overall health of the troops. Such a situation allowed evaluation of USAR troop training and preparedness in field sanitation. Results indicate that field sanitation training needs to be improved at the unit level.

Effect of dietary zinc on larval burdens, tissue eosinophil numbers, and lysophospholipase activity of Ascaris suum infected mice.

The effect of dietary zinc on larval burdens, tissue eosinophil numbers, and lysophospholipase (LPL) activity in the lungs and livers of BALB/c mice infected with Ascaris suum was evaluated. A suum larval numbers were increased in both liver and lungs in low zinc groups during primary and secondary infection as assessed at days 2 and 7 after egg administration. In the same groups, LPL activity and eosinophil numbers were reduced at both time points and in both tissues, with the exception of lung eosinophils in nonimmunized mice, since these animals did not develop an eosinophil response during primary infection.

Effect of dietary magnesium on Ascaris suum infections of mice.

Low amounts of dietary magnesium affected the inflammatory tissue response in nonimmunized mice differently than in immunized mice. Eosinophil numbers and LPL activity in lung tissue following infection with A. suum larvae were altered by the level of magnesium in the diets of mice. Average or higher dietary levels of magnesium resulted in decreased numbers of lung larvae indicating an overall protective effect. Increases in eosinophil numbers or LPL activity were not directly related to the numbers of larvae/lungs. Larvae/livers, eosinophil numbers, and LPL activity were affected by the types of magnesium diets that mice received. Nonimmunized mice had differences in larvae/liver (at 2 days and 7 days pi) and LPL activity (at 2 days pi). Immunized mice had varying findings at 2 days pi but a direct relationship between dietary magnesium and numbers of larvae, numbers of eosinophils, and liver LPL activity at 7 days pi.

Cytotoxicity of mouse serum and peritoneal fluid for Ascaris suum infective larvae.

Serum from BALB/c mice infected with Ascaris suum resulted in 51Cr release from A. suum infective larvae during in vitro incubation. Peritoneal fluid from infected or noninfected BALB/c mice also produced in vitro release of 51Cr from A. suum larvae. 51Cr release did not occur when anti-A. suum serum or peritoneal fluid from infected or noninfected mice were heat-inactivated. Serum and peritoneal fluid from infected or noninfected AKR-C5 deficient mice did not generate 51Cr release from A. suum larvae.

Alterations in Ascaris suum larval burdens, eosinophil numbers, and lysophospholipase activity associated with low levels of dietary iron.

The effect of various amounts of dietary iron on the immune response was investigated using BALB/cAnNCr/BR mice infected with Ascaris suum. Changes in numbers of larvae, numbers of eosinophils, and levels of lysophospholipase (LPL) activity in lung or liver tissues were analyzed from nonimmune and immunized mice at 2 and 7 days postinfection (PI). Various iron diets did not influence the numbers of tissue larvae, eosinophils, or the LPL activity in lungs or livers of nonimmunized mice at various times after infection. Lung and liver LPL activity was reduced in immunized mice without significant changes in larval numbers at 2 days PI. At 7 days PI, lung and liver LPL activity, eosinophil numbers, and numbers of larvae were increased in immunized mice receiving low iron diets. Results confirm that low iron diets affect the host response to A. suum.

Seminal vesicle and coagulating gland growth induced by intraperitoneal inoculation of fungi in mice.

The effect of fungi on the growth of body organs in mice was investigated. Single, intraperitoneal injections of yeasts (Cryptococcus albidus, Saccharomyces cerevisiae, Schizosaccharomyces octosporus) or molds (Aspergillus niger, Geotrichum candidum, Mucor haemalis) induced an increase in the mass of seminal vesicles and coagulating glands independent of whole body weight changes in mice.

Lysophospholipase activity of Mycobacterium smegmatis.

Lysophospholipase (LPL) activity found in Mycobacterium smegmatis was characterized. LPL activity was found to exist in high levels in two-to-10-day-old cultures. The enzyme assay was run using 1.4 X 10(9) viable bacteria at an incubation time of 24 h. Enzyme activity was detected between 1 degree C and 80 degrees C with maximal activity between 40 degrees C and 60 degrees C. LPL activity was maximal at pH 9.0, with activity ranging between pH 3.0 and 10.0.

Seminal vesicle growth induced by Ascaris suum infection.

This study was designed to determine the effect of Ascaris suum infection upon growth of mouse vesicular glands. Mice were infected with varying dosages of A. suum eggs and killed after six weeks. Results indicated a dose dependent increase in seminal vesicle weight, independent of total body weight.

Fc and C3b receptor changes on mouse peritoneal leucocytes following stimulation with an extract of Ascaris suum.

Changes in IgG-Fc and IgM-C3b receptors of mouse peritoneal leucocytes after in vivo stimulation with Ascaris suum adult extract were studied. Erythrocyte IgG-Fc rosettes were found to initially be decreased with A. suum stimulated neutrophils, eosinophils and macrophages in comparison with nonstimulated cells. IgG-Fc rosettes then increased with time and remained high for a 60 min exposure time. IgM-C3b rosette formation was lower with A. suum stimulated leucocytes throughout 60 min of exposure and dropped off dramatically after 30 min. Unstimulated leucocytes formed IgM-C3b rosettes sooner and maintained them at higher levels for a longer period of time than stimulated cells.

Dextran sulfate-induced peritoneal lysophospholipase activity varies among mouse strains.

Lysophospholipase (LPL) activity resulting from the intraperitoneal injection of dextran sulfate (DS) was studied in different mouse strains. AKR/J and BALB/cByJ mouse strains showed decreased LPL levels when a low molecular weight DS was injected but increased LPL activity when high molecular weight DS was injected intraperitoneally. C57BL/6 mice had increased LPL activity with low molecular weight DS but decreased LPL activity with high molecular weight DS. All three mouse strains showed increased peritoneal-cell changes when injected with DS of a molecular weight of 79,000.