Prevalence of Schistosoma haematobium Infection among School-Age Children in Afar Area,Northeastern Ethiopia

In this study, the prevalence and intensity of Schistosoma haematobium infection was determined among school-age children living in the Middle and Lower Awash Valley, Afar Regional State of Ethiopia. Between February and May 2014, urine samples were collected from 885 school-age children (5–16 years of age) from the Middle (n = 632; 4 villages) and Lower (n = 253; 3 villages) Awash Valley. All samples were processed using urine filtration to detect and quantify S. haematobium eggs. In addition, a subset of the urine samples was tested for hematuria using a urine dipstick (n = 556). The overall prevalence was 20.8% (95% Confidence Interval (CI) = 18.1%, 23.5%), based on urine filtration but the prevalence considerably varied across villages both in the Middle (from 12.5% to 37.0%) and Lower Awash Valley (from 0 to 5.3%). The overall mean urine egg count (UEC) among the infected children was 4.0 eggs/10 ml of urine (95% CI = 2.43, 5.52). The infection intensity varied from 0.4 eggs/10 ml of urine to 7.7 eggs/10 ml of urine in the Middle Awash Valley, and from 0 to 1.1 eggs/10 ml of urine in Lower Awash Valley. Age and sex were not associated with S. haematobium infection based on the multivariable logistic regression model. The prevalence of hematuria was 56.3% (95% CI = 52.2%, 60.4%) among a subset of the study participants (556) examined using the urine dipstick. The prevalence of hematuria also varies with villages from 8.3% to 93.2%. In conclusion, the prevalence of S. haematobium infection in the Middle Awash Valley was high and it varies across villages. Hence, children living in the present study villages of the Middle Awash Valley need to be treated with praziquantel to reduce morbidity and disrupt transmission.     

Schistosomiasis in Cross River State, Nigeria: 1. Prevalence and intensity of infection in Adim, Akamkpa Local Government Area

Mid-stream urine was randomly collected from 248 subjects in Adim. Blood and protein concentrations were determined semi-quantitatively using Combi-7 reagent strips. The urine samples were then processed and any ova of Schistosoma haematobium present were counted per 10 ml urine. Fresh stool samples were also randomly collected, processed and examined for S. masoni and other helminthic ova. The prevalence of S. haematobium in the area was 43.5% and this was found to be age-related but not sex-related. Mean egg count was 137.2 per 10 ml urine. Intense haematuria of 250 ery/microliters and proteinuria of 500 mg/dl accompanied the high egg counts. The stool examination showed no cases of Manson's schistosomiasis but polyparasitism with other intestinal helminths was common particularly among children under 10 years old. This is the first report of urinary schistosomiasis in this area and the high prevalence rate is consistent with the rice farming occupation of the natives of the area. The sensitive nature and the case of application of the reagent strips in determining heavy infections by measuring haematuria and proteinuria is once again confirmed.     

Spatial Distributions of HIV Infection in an Endemic Area of Western Kenya: Guiding Information for Localized HIV Control and Prevention

HIV is still a major health problem in developing countries. Even though high HIV-risk-taking behaviors have been reported in African fishing villages, local distribution patterns of HIV infection in the communities surrounding these villages have not been thoroughly analyzed. The objective of this study was to investigate the geographical distribution patterns of HIV infection in communities surrounding African fishing villages. In 2011, we applied age- and sex-stratified random sampling to collect 1,957 blood samples from 42,617 individuals registered in the Health and Demographic Surveillance System in Mbita, which is located on the shore of Lake Victoria in western Kenya. We used these samples to evaluate existing antibody detection assays for several infectious diseases, including HIV antibody titers. Based on the results of the assays, we evaluated the prevalence of HIV infection according to sex, age, and altitude of participating households. We also used Kulldorff’s spatial scan statistic to test for HIV clustering in the study area. The prevalence of HIV at our study site was 25.3%. Compared with the younger age group (15–19 years), adults aged 30–34 years were 6.71 times more likely to be HIV-positive, and the estimated HIV-positive population among women was 1.43 times larger than among men. Kulldorff’s spatial scan statistic detected one marginally significant (P = 0.055) HIV-positive and one significant HIV-negative cluster (P = 0.047) in the study area. These results suggest a homogeneous HIV distribution in the communities surrounding fishing villages. In addition to individual behavior, more complex and diverse factors related to the social and cultural environment can contribute to a homogeneous distribution pattern of HIV infection outside of African fishing villages. To reduce rates of transmission in HIV-endemic areas, HIV prevention and control programs optimized for the local environment need to be developed.     

Urinary schistosomiasis in southern Ghana: 1. Prevalence and morbidity assessment in three (defined) rural areas drained by the Densu river

Epidemiological studies on urinary schistosomiasis were carried out in eight villages in the Ga and Akuapem South districts in Ghana. Single urine samples were collected from individuals aged 5 years and above between 10.00 and 14.00 h. The samples were examined for the presence of Schistosoma haematobium eggs using a filtration technique. Indirect morbidity was determined as the presence of microhaematuria and proteinuria using reagent strips, and macrohaematuria was recorded with the naked eye. Out of the study population of 3912 subjects, 2562 (65.5%) submitted urine samples. The prevalence of a Schistosoma haematobium infection ranged between 54.8 and 60.0%. Infection rates increased by age with a peak in the 10-19 years category, and decreased with increasing age. Disease prevalence was higher in males aged 15 years and above in Areas 2 (Ntoaso and Sansami Amanfro) and 3 (Dom Faase, Papase, Chento and Gidi Kope), whereas it was higher among males aged 10 years and above in Area 1 (Ayikai Doblo and Akramaman). The intensity of infection was highest among children aged 10-14 years in most of the villages. More than half of egg-positive children in this age group had a heavy infection (100 eggs and above in 10 ml of urine). Although both egg-positive and egg-negative individuals manifested variable degrees of macro- or micro-haematuria, microhaematuria was more prevalent among egg-positives (chi(2)=918.5, d.f.=1, P<0.01). The degree of microhaematuria and proteinuria were significantly associated with the intensity of the infection. These results indicate a high transmission of disease in the study area.     

Schistosoma haematobium infections in preschool children from two rural communities in Ijebu East, south-western Nigeria

There is an urgent need for information on schistosomiasis in preschool children, who are often excluded in mass treatment programmes. The prevalence and intensity of Schistosoma haematobium infection were determined in preschool children aged ≤ 6 years in two rural communities in Ijebu East, south-western Nigeria. Two urine samples each were collected from 83 preschool children from the two communities, tested for microhaematuria using reagent strips and then processed and examined with a microscope for S. haematobium eggs. Focus group discussions on perceptions of the disease and water contact practices were held in the communities with their guardians, caregivers and preschool children, using an interview guide. The prevalence of S. haematobium in the two communities was 14 (16.9%), with no significant differences (P = 0.661) in infection rate between boys (18.4%) and girls (14.7%). Both prevalence and intensity of infection did not increase significantly with age in both Korede and Obada community. However, there were significant differences in prevalence of infection between the two communities (P = 0.035). There was no association (P = 0.750) between intensity in boys (0.176 eggs/10 ml urine) and girls (0.110 eggs/10 ml urine). Focal group discussions with guardians and caregivers revealed that preschool children acquired infection early in their lives through exposure to infected stream water by their mothers, while the older children visit the stream for playing, bathing and swimming. It has therefore become imperative for preschool children to be included in the planning of schistosomiasis intervention programmes as a means of reducing transmission.     

Long-term outcomes of school-based treatment for control of urinary schistosomiasis: a review of experience in Coast Province, Kenya

Urinary schistosomiasis remains a significant burden for Africa and the Middle East. The success of population-based control programs will depend on their impact, over many years, on Schistosoma haematobium reinfection and associated disease. In a multi-year (1984-1992) control program in Kenya, we examined risk for S. haematobium reinfection and late disease during and after annual school-based treatment. In this setting, long-term risk of new infection was independently associated with location, age, hematuria, and incomplete treatment, but not with sex or frequency of water contact. Thus, very local environmental features and age-related factors played an important role in S. haematobium transmission, such that population-based control programs should optimally tailor their efforts to local conditions on a village-by-village basis. In 2001-2002, the late benefits of earlier participation in school-based antischistosomal therapy were estimated in a cohort of formerly-treated adult residents compared to never-treated adults from the same villages. Among age-matched subjects, current infection prevalence was lower among those who had received remote therapy. In addition, prevalence of bladder abnormality was lower in the treated group, who were free of severe bladder disease. Treatment of affected adults resulted in rapid resolution of infection and any detectable bladder abnormalities. We conclude that continued treatment into adulthood, as well as efforts at long-term prevention of infection (transmission control) are necessary to achieve optimal morbidity control in affected communities.     

The epidemiological status of urogenital schistosomiasis among reproductive aged individuals in the Tiko Health Area- a semi-urban setting in the Mount Cameroon area

BackgroundUrogenital schistosomiasis (UGS) caused by S. haematobium has enormous reproductive health consequences including infertility. Reproductive aged individuals are a neglected group and not included in control programs in Cameroon. This study investigated the prevalence and severity of S. haematobium infection in the context of gender and socio-economic structures that shape behaviour among reproductive aged individuals living in Tiko, a semi-urban setting, Cameroon.Methodology/Principal findingsA cross-sectional study was carried out in the Tiko Health District (THD) between May to September 2019. Consenting individuals were enrolled using a convenient sampling technique and administered a semi-structured questionnaire to document data on socio-demographic and stream contact behaviour. A urine sample was collected and screened for the presence of S. haematobium ova using reagent strips, filtration and microscopy. The overall prevalence of S. haematobium infection was 22.8% (95% CL: 19.27–26.73) with geometric mean egg load of 18.74 (range: 1–1600) per 10ml of urine. Younger age group (15 – 20years) (OR: 5.13; 95% CL: 1.35–19.42), male (OR: 2.60 3.07; 95% CL: 1.54–4.40) and awareness of UGS (OR: 1.73; 95% CL: 1.02–2.95) were associated with higher odds of exposure to infection. Significantly higher intensity of infection was seen in males, singles and in the age group 15–30 years. It is worth noting that males carried out more activities which entailed longer duration in streams.Conclusion/SignificanceThe prevalence obtained shows that Tiko is a moderate-risk area for UGS with underlying morbidity-inducing infection intensity. The severity of the infection is more in males. Awareness of the disease is not enough to protect these communities from infection, but provision of public infrastructures and health education will limit contact with infested water and thus curtail the infection. There is an urgent need to involve all age groups in control programs.     

The diagnostic value of haematuria and proteinuria in Schistosoma haematobium infection in southern Nigeria.

Haematuria and proteinuria as detected by chemical reagent strips correlated moderately (r = 0.7) with prevalence and intensity of infection with Schistosoma haematobium in an area of Anambra State, Nigeria. Differences attributable to age and sex were also reflected in a similar pattern, all peaks occurring in the 5-14 year age group. The differences observed with varying levels of intensity and haematuria at both 10 and 50 erythrocytes/microliter (p < 0.001) and proteinuria at 0.3 g/dl (p < 0.01) were statistically significant. At a proteinuria level of 1 g/dl, the observed differences were however not statistically significant (p > 0.5). The percentage of specimens from children (0-14 years) positive for S. haematobium eggs and with at least traces of haematuria and proteinuria (63.4% and 95%, respectively) was higher than in adults (33.3% and 80.2%, respectively). All individuals with more than 50 eggs/10 ml of urine were correctly identified using both indices either separately or in combination. For egg counts of less than 50 eggs/10 ml of urine, false diagnosis occurred in only 5% of all specimens examined. The sensitivity and specificity of haematuria and proteinuria at trace quantities was very high, but haematuria had a higher predictive value for a positive test (PvPt) and was considered the overall better indicator. A combination of both indices did not significantly increase the PvPt. When trace haematuria and moderate proteinuria were combined, both the sensitivity, specificity and PvPt were all above 90%, giving the best overall values in all the combinations made.     

Prevalence of Helicobacter pylori infection in Warao lineage communities of Delta Amacuro State, Venezuela

The purpose of this study was the evaluation of Helicobacter pylori infections in children and adults from two indigenous communities of Delta Amacuro State, Venezuela, that differ in hygienic conditions of the housing. The evaluation was performed in 98 children (mean age 7 +/- 3.37 years) and their mothers (33.96 +/- 13.77 years) from two communities of Warao lineage. Anti-H. pylori serum IgG and secretory anti-H. pylori IgA antibodies were determined, as well as total secretory IgA and H. pylori antigens in feces. Serological prevalence of H. pylori infection was 38% in children and 84% their in mothers. Children from the community that had the most deficient sanitary and hygienic conditions had significantly lower titers of specific IgG antibodies and total secretory IgA (P<0.0001) and a high percentage of them had H. pylori antigens in their feces (P<0.0001). The levels of specific IgA were similar in both groups. The results indicate that in these populations there is a high prevalence of H. pylori infection and that poor hygienic conditions can increase the risk of infection and damage to the gastrointestinal tract.     

Abdominal vagotomy decreased the number of ova shed and serum progesterone levels on estrus in the cyclic hamster.

The effects of abdominal vagotomy (AVGT) on ovarian function were studied in cyclic hamsters. AVGT significantly decreased the number of ova shed (AVGT: 10.5 +/- 1.5 ova/hamster, sham: 15.8 +/- 0.7 ova/hamster; P less than 0.05) and serum progesterone levels (AVGT: 2.1 +/- 0.3 ng/ml, sham: 3.9 +/- 0.7 ng/ml; P less than 0.05) on the morning of estrus. However, progesterone concentrations in the corpora lutea and non-luteal ovary on estrus in the AVGT and sham groups were similar. The serum estradiol levels in both groups on proestrus increased from 0900 h (AVGT: 75 +/- 10 pg/ml, sham: 72 +/- 6 pg/ml) to 1500 h (AVGT: 204 +/- 27 pg/ml, sham: 196 +/- 35 pg/ml) but there was no significant difference between the two groups. Partial degranulation of ovarian mast cells was not increased in the AVGT group. Also, vasoactive intestinal peptide (VIP) content in the ovary was not increased by AVGT at 0900 h on proestrus (AVGT: 60.1 +/- 16.8 pg/ovary, sham: 37.2 +/- 14.3 pg/ovary). These results indicated that AVGT interferes with normal ovulation and results in an increase in the number of atretic follicles, but that these effects by AVGT seemed not to be mediated through ovarian mast cells and VIP.     

Effects of time of day, gender, and menstrual cycle phase on the human response to a water load

Estrogen and progesterone interference with renal actions of arginine vasopressin (AVP) has been shown. Thus we hypothesized that women will have a higher water turnover than men and that the greatest difference will be during the luteal phase of the menstrual cycle. Seven men (32 +/- 3 yr) and six women (33 +/- 2 yr) drank 12 ml water/kg lean body mass on different days at 0800 and at 2000 following 10 h of fast and a standardized meal at 0600 and 1800. Women participated on days 4-11 and 19-25 of the menstrual cycle. Initial urine and plasma osmolalities and urine flow rates were similar in all experiments. The cumulative urine voided over 3 h following the morning drink was less in men (73 +/- 12% of the water load) compared with women in either the follicular (100 +/- 3%) or luteal phases (102 +/- 10%) of the menstrual cycle. Nighttime values (30-43% of the water load) were lower in all experiments and were not different between sexes or menstrual cycle phases. Plasma AVP was higher at night and may contribute to this diurnal response. The data are generally consistent with the stated hypothesis; however, possibly owing to the greatly reduced urine flow in both sexes at night, a difference between sexes was not observed at that time.     

Prevalence of hepatitis A virus infection in Afro-Brazilian isolated communities in Central Brazil

To investigate hepatitis A virus (HAV) infection rates among isolated African-descendant communities in Central Brazil, 947 subjects were interviewed about demographic characteristics in all 12 isolated Afro-descendant communities existing in the state of Mato Grosso do Sul, Central Brazil, between March 2002 and November 2003. Blood samples were collected and sera were tested for HAV antibodies (total and IgM anti-HAV) by enzyme-linked immunosorbent assay. The overall prevalence of HAV infection was 75.6% (95% CI: 72.7-78.3), ranging from 55.4 to 97.3%, depending on the communities studied. The prevalence of anti-HAV increased significantly with age, from 13.8% in the age 0-5 age group to 96.6% in those older than 40 years. The findings point out an intermediate endemicity of HAV infection in some Afro-Brazilian isolated communities in Central Brazil. In addition, the high proportion of susceptible young subjects could be target of future HAV vaccination programs.     

Genitourinary schistosomiasis among pre-primary schoolchildren in a rural community within the Cross River Basin, Nigeria

In Africa, most schistosomiasis control programmes defined the age 5-19 years as the target population for nationwide control through the school systems, excluding the under fives. A study was therefore undertaken to determine the prevalence and intensity of genitourinary schistosomiasis in children aged 0-5 years (pre-primary) in Adim, a rural and endemic community within the Cross River Basin, Nigeria. Of the 126 children examined, 25 (19.8%) were infected with Schistosoma haematobium, with no significant difference (P > 0.05) in infection rates between boys (21.1%) and girls (18.2%). Both prevalence and intensity of infection increased significantly (P 0.05) between intensity in boys (6.2 eggs/10 ml urine) and girls (5.6 eggs/10 ml urine). A total of 32.5 and 27.8% of the children had haematuria and proteinuria, respectively; it was not gender specific (P > 0.05). Six species of snail were encountered, with Bulinus globosus being the most abundant and widespread. The results of this study have shown that pre-primary schoolchildren are a source of transmission of schistosomiasis in endemic communities and should be integrated into any control intervention.     

Prevalence and intensity of Toxocara canis (Werner, 1782) in dogs and its potential public health significance in Ile-Ife, Nigeria

A study on the prevalence and intensity of Toxocara canis (Werner, 1782) in dogs was carried out in Ile-Ife, Nigeria. Faecal samples were collected from 269 dogs between January and December 2004, processed by the Kato-Katz technique and then examined for T. canis eggs. The prevalence of T. canis obtained was 33.8%. The intensity of infection, measured as mean egg count per gram of faeces ( +/- SEM) was 393.8 +/- 83.4. The prevalence and intensity of T. canis in dogs aged 0-6 months were significantly higher (P < 0.05) than older age groups. The prevalence and intensity of T. canis infection were significantly higher in males than in female dogs (P < 0.05). Since T. canis is known to cause visceral larva migrans (VLM) in young children, there is the possibility that the high prevalence of T. canis infection obtained in this study might constitute an important risk factor for transmission to humans. Therefore, there is the need to educate the residents of Ile-Ife on the danger of close association of their children with household pets.     

Malaria, schistosomiasis, and intestinal helminths in relation to microdams in Tigray, northern Ethiopia.

A survey was undertaken in Tigray, Northern Ethiopia, to assess the prevalence of malaria, schistosomiasis, and intestinal helminths in relation to microdams. The survey took place from March to June 1995, during the dry season, at 41 microdams. At each site the village nearest the dam (within thirty minutes walk) was selected, ten households were randomly chosen, and all family members were examined for malaria and intestinal parasites. The overall study sample was 2271 people, of all age groups. Plasmodium falciparum infection was documented in four villages (at 10% of microdams); prevalence was 1.2% (range 0-20% by village). Larvae of Anopheles gambiae s.l. were found at one microdam. Infection with intestinal schistosomiasis was documented in 20 villages (at 49% of microdams), and one third of those infected had moderate to heavy infections. Biomphalaria species, the intermediate host snails of Schistosoma mansoni, were found at 16 microdams (39%), and snails infected by mammalian cercariae were found in one locality. Infections with soil-transmitted nematodes were prevalent: hookworm was detected in more than two thirds of the villages, and Ascaris lumbricoides and Trichuris trichiura were present in almost half of the villages. Out of 2078 stool examinations, the prevalence of S. mansoni infection was 7.2% (range 0-48% by village), of A. lumbricoides 2.3% (range 0-31%), of T. trichiura 2.4% (range 0-21%), and of hookworm 8.9% (range 0-78%). The prevalence of malaria, S. mansoni and hookworm was higher at altitudes below 2000 metres above sea level. S. mansoni was more prevalent in microdams built more than 5 years before the survey, while T. trichiura was more prevalent at recently constructed microdams. The widespread distribution of schistosomiasis and intestinal helminths, and the presence of malaria infection during the dry season confirm that microdams create favourable conditions for the transmission of these parasitic diseases. Health safeguards must be incorporated into the planning, construction, and operation of microdams and irrigation systems in order to prevent or reduce these diseases. In areas with high prevalence, control activities should be intensified.     

A Community-Based Study of Factors Associated with Continuing Transmission of Lymphatic Filariasis in Leogane,Haiti

Seven rounds of mass drug administration (MDA) have been administered in Leogane, Haiti, an area hyperendemic for lymphatic filariasis (LF). Sentinel site surveys showed that the prevalence of microfilaremia was reduced to <1% from levels as high as 15.5%, suggesting that transmission had been reduced. A separate 30-cluster survey of 2- to 4-year-old children was conducted to determine if MDA interrupted transmission. Antigen and antifilarial antibody prevalence were 14.3% and 19.7%, respectively. Follow-up surveys were done in 6 villages, including those selected for the cluster survey, to assess risk factors related to continued LF transmission and to pinpoint hotspots of transmission. One hundred houses were mapped in each village using GPS-enabled PDAs, and then 30 houses and 10 alternates were chosen for testing. All individuals in selected houses were asked to participate in a short survey about participation in MDA, history of residence in Leogane and general knowledge of LF. Survey teams returned to the houses at night to collect blood for antigen testing, microfilaremia and Bm14 antibody testing and collected mosquitoes from these communities in parallel. Antigen prevalence was highly variable among the 6 villages, with the highest being 38.2% (Dampus) and the lowest being 2.9% (Corail Lemaire); overall antigen prevalence was 18.5%. Initial cluster surveys of 2- to 4-year-old children were not related to community antigen prevalence. Nearest neighbor analysis found evidence of clustering of infection suggesting that LF infection was focal in distribution. Antigen prevalence among individuals who were systematically noncompliant with the MDAs, i.e. they had never participated, was significantly higher than among compliant individuals (p<0.05). A logistic regression model found that of the factors examined for association with infection, only noncompliance was significantly associated with infection. Thus, continuing transmission of LF seems to be linked to rates of systematic noncompliance.     

Systems for collection of urine in the captive common marmoset, Callithrix jacchus

Two systems are described for the collection of 24 h urine samples from the common marmoset (Callithrix jacchus). Using 84 adult animals, 1210 24-h samples were collected. Mean urinary excretion was 14.4 +/- 7.5 ml/24 h (n = 1210, mean +/- SD). No differences were observed between sexes (for 52 females, 24 h volume = 15.1 +/- 8.0 ml; for 32 males, 24 h volume = 12.5 +/- 6.0 ml). No significant differences were observed between pregnant and non-pregnant females with respect to 24 h urine volume, and bilateral gonadectomy did not influence subsequent urinary excretion in either sex. For 161 pairs of observations, the intake of drinking water (11.7 +/- 10.2 ml/24 h) and the volume of urine excreted (12.6 +/- 7.1 ml/24 h) showed a positive correlation (r = 0.406 d.f. 159, P less than 0.001: y = 0.558x + 4.247).     

Assessment of loiasis and outcomes of ivermectin masstreatment in Ijebu-North, Nigeria

A total of 286 individuals from 3 selected communities (Areedi-Aje, Ipakodo/Ojokodo, and Ijebu-Igbo) of Ijebu-North, southwestern Nigeria were examined for Loa loa microfilaremia using finger prick blood smear, between December 2008 and March 2009. Rapid assessment procedure for loiasis (RAPLOA) was used to obtain information, from 187 Ijebu-Igbo residents, on adverse reactions experienced from retrospective treatments with ivermectin and history of eye worm. Only 33.9% of the respondents reported having had a history of eye worm while 33.2% had microfilaremia. The demographic factor of gender was not significant determinants of the prevalence (P>0.05) while age was significant (P<0.05). The highest prevalence of eye worm history and microfilaremia were recorded in 61-70 and 15-20 years of age categories, respectively. Ijebu-Igbo had 27.3% eye worm history, 32.1% microfilaremia, and the highest intensity of 140 microfilariae (mf)/ml. Ipakodo area had the highest eye worm history of 54.4% and the highest intensity of 420 mf/ml. Areedi-Aje had the highest occurrence of 45.2% microfilaremia and the highest intensity of 460 mf/ml. Predictably, Areedi-Aje and Ipakodo areas were high risk communities. The low intensity of L. loa infection with an insignificant (2.1%; P>0.05) adverse reactions from 187 subjects involved in the retrospective ivermectin administration confirmed that ivermectin delivery may be considered safe. The community-directed treatment with ivermectin (CDTI) programme was most probably responsible for the low prevalence and intensity.     

Seasonal changes in prevalence and intensity of Hypoderma actaeon in Cervus elaphus from central Spain

Hypodermosis in red deer, Cervus elaphus Linnaeus (Artilodactyla: Cervidae), caused by the warble fly, Hypoderma actaeon Latreille (Diptera: Oestridae), was studied at Quintos de Mora (Toledo, Spain) over a one-year period between October 1994 and September 1995. One hundred and twenty-five red deer were examined for the presence of warble fly larvae. The prevalence of warbles was 44.8% and the intensity of infection was 38.29 (SD +/- 61.32) warbles/deer infected. Clear seasonal variations were observed in prevalence and intensity, with the highest values in the autumn and winter. Statistically significant differences were observed in prevalence and intensity among age groups. In contrast, no differences were found in prevalence and intensity between males and females.