Prevalence of Pediculus Capitis Infestation Among School Children of Chinese Refugees Residing in Mountainous Areas of Northern Thailand

An epidemiologic survey of Pediculus capitis infestation among Akka aboriginal and Han children of Chinese refugees living in mountainous areas at elevations of 1,100 to 1,400 m in Chiang-Rai Province of northern Thailand was conducted during January 2003. Of the 303 children examined, 43 (14.2%) had P. capitis infestation. The overall infestation rate for P. capitis in Akka children (29.3%, 12/41) was significantly higher than that in Han children (11.8%, 31/262; c2 = 8.161, p = 0.002). The prevalence in Akka (52.2%, 12/23) and Han girls (19.7%, 31/157) was higher than that in Akka (0%) and Han boys (0%), respectively (p < 0.001), and the prevalence was higher in Akka girls than in Han girls (c2 = 10.978, p = 0.001). The high prevalence of P. capitis infestation among these girls was possibly due to poor environmental hygiene and unavailability of sufficient water

Prevalence of intestinal parasitic infections among school children in capital areas of the Democratic Republic of São Tomé and Príncipe, West Africa

Background: Although the Democratic Republic of Sao Tome and Principe (DRSTP) has undertaken school children-based deworming programs against intestinal parasitic infections (IPIs) using a single dose of mebendazole annually since 2005, it remains unclear as to the outcome to date. The present study intends to  investigate the recent IPIs status among school children living in capital areas of the DRSTP.Methods: A total of 252 school children (121 boys and 131 girls) of grades 4 and 5 from 4 primary schools located in the capital areas participated in the present study and their fresh fecal specimens were examined for the presence of any parasites using the merthiolate- iodine-formaldehyde concentration method as conducted.Results: The overall prevalence of IPIs was 64.7% (163/ 252). No significant gender difference in prevalence between boys (67.8%) and girls (61.8%) was found (p = 0.3). The majority of school children were infected with a single species of parasite (55.8%). Altogether, 12 different intestinal parasite species were identified in DRSTP school children, of which 9 species were pathogenic and the remaining 3 were non-pathogenic.Conclusion: Improving the detection method, sanitation facilities and personal hygiene as well as utilizing combined drugs are all important measures to greatly reduce IPIs in DRSTP school children.Keywords: Democratic Republic of Sao Tome and Principe, school children, intestinal parasitic infection

Molecular approaches to deploy singlet oxygen in a Leishmania model as an unassailable biocide for disease mitigation and vector control

Singlet oxygen (1O2) is a potent biocide potentially deployable for integrated control of tropical diseases and their insect vectors. This very short-lived free radical is highly destructive of cellular molecules when generated intracellularly. Most organisms, including parasites and vectors, are defenseless against 1O2 except for plants, which produce it abundantly during photosynthesis, hence, the acquisition of specific mechanisms for its detoxification. In the presence of O2 under physiological conditions, certain dyes or photosensitizers (PS), e.g., porphyrins and phthalocyanines (PC), are excitable by light to produce biocidal 1O2. Its half-life is in the order of microseconds, necessitating its intracellular generation in order to harness its biocidal activity most effectively. This is achievable by loading cells with PS for excitation with light to produce 1O2in situ. One example to achieve this is the genetic engineering of Leishmania to complement its inherent defects in porphyrin biosynthesis, resulting in cytosolic accumulation of abundant PS in the form of uroporphyrin 1 (URO). Another example is the chemical engineering of PC for hydrophilicity, thereby facilitating the endocytosis of such PS by cells. Leishmania loaded with cytosolic URO and endosomal PC are inactivated by the 1O2 produced via light-activation of these PS in the two different cell compartments. The inactivated Leishmania are nonviable, but have their natural vaccines and adjuvants well-preserved for prophylactic vaccination against experimental leishmaniasis. 1O2-inactivated Leishmania is potentially useful to serve as a platform for the safe and effective delivery of transgenically add-on vaccines against malignant and viral diseases in experimental models. Hydrophilic and cationic PC were also shown experimentally to act as a new type of dim light-activable insecticides, i.e., their mosquito larvicidal activities with &lt;µM LD50 values. Similar results are expected by studying PC in additional laboratory insect models. A significant advantage has long been attributed to this type of insecticide, i.e., their aversion to a selection of genetic variants for resistance. An additional advantage of PC is their excitability to produce insecticidal 1O2 with deep-penetrating red or infrared light invisible to most insects, thereby potentially increasing the range and scope of targetable insect vectors

Brain injury-associated biomarkers of TGF-beta1, S100B, GFAP, NF-L, tTG, AbetaPP, and tau were concomitantly enhanced and the UPS was impaired during acute brain injury caused by Toxocara canis in mice

BACKGROUND: Because the outcomes and sequelae after different types of brain injury (BI) are variable and difficult to predict, investigations on whether enhanced expressions of BI-associated biomarkers (BIABs), including transforming growth factor beta1 (TGF-beta1), S100B, glial fibrillary acidic protein (GFAP), neurofilament light chain( NF-L), tissue transglutaminases (tTGs), beta-amyloid precursor proteins (AbetaPP), and tau are present as well as whether impairment of the ubiquitin-proteasome system (UPS) is present have been widely used to help delineate pathophysiological mechanisms in various BIs. Larvae of Toxocara canis can invade the brain and cause BI in humans and mice, leading to cerebral toxocariasis (CT). Because the parasitic burden is light in CT, it may be too cryptic to be detected in humans, making it difficult to clearly understand the pathogenesis of subtle BI in CT. Since the pathogenesis of murine toxocariasis is very similar to that in humans, it appears appropriate to use a murine model to investigate the pathogenesis of CT. METHODS: BIAB expressions and UPS function in the brains of mice inoculated with a single dose of 250 T. canis embryonated eggs was investigated from 3 days (dpi) to 8 weeks post- infection (wpi) by Western blotting and RT-PCR. RESULTS: Results revealed that at 4 and 8 wpi, T. canis larvae were found to have invaded areas around the choroid plexus but without eliciting leukocyte infiltration in brains of infected mice; nevertheless, astrogliosis, an indicator of BI, with 78.9~142.0-fold increases in GFAP expression was present. Meanwhile, markedly increased levels of other BIAB proteins including TGF-beta1, S100B, NF-L, tTG, AbetaPP, and tau, with increases ranging 2.0~12.0-fold were found, although their corresponding mRNA expressions were not found to be present at 8 wpi. Concomitantly, UPS impairment was evidenced by the overexpression of conjugated ubiquitin and ubiquitin in the brain. CONCLUSION: Further studies are needed to determine whether there is an increased risk of CT progression into neurodegenerative disease because neurodegeneration-associated AbetaPP and phosphorylated tau emerged in the brain. DOI: 10.1186/1471-2334-8-8

Prevalence of Pediculus Capitis Infestation Among School Children of Chinese Refugees Residing in Mountainous Areas of Northern Thailand

An epidemiologic survey of Pediculus capitis infestation among Akka aboriginal and Han children of Chinese refugees living in mountainous areas at elevations of 1,100 to 1,400 m in Chiang-Rai Province of northern Thailand was conducted during January 2003. Of the 303 children examined, 43 (14.2%) had P. capitis infestation. The overall infestation rate for P. capitis in Akka children (29.3%, 12/41) was significantly higher than that in Han children (11.8%, 31/262; c2 = 8.161, p = 0.002). The prevalence in Akka (52.2%, 12/23) and Han girls (19.7%, 31/157) was higher than that in Akka (0%) and Han boys (0%), respectively (p < 0.001), and the prevalence was higher in Akka girls than in Han girls (c2 = 10.978, p = 0.001). The high prevalence of P. capitis infestation among these girls was possibly due to poor environmental hygiene and unavailability of sufficient water

Experimental Ocular Toxocariasis in Mice Infected with Long-term-maintained Embryonated Eggs of Toxocara canis

Ocular injury to ICR mice from embryonated eggs of Toxocara canis, which had been maintained in 2% formalin for 14 months at 4°C, was evaluated by microscopic and pathologic assessments at 1, 2, 3, 5, 7, 28, 56, 84, 112, 140, 168, 196, 294 and 469 days post infection (DPI). On each date, three infected mice and two age-matched uninfected control mice were sacrificed; left eyeballs from infected mice were examined for larvae under a dissecting microscope while all right eyeballs were embedded in paraffin for histologic study. No larvae were observed in the left eyeball of any of the 42 infected mice, while pathologic changes were observed in right eyeballs. Pathologically, the predominant changes were retinal detachment, iridocyclitis, and pars planitis, followed by optic nerve papillitis and superficial infarcts, as observed in one of three infected mice per group at 56, 140, and 168 DPI, respectively. No infiltrating cells surrounding the larvae in the retina were observed in the infected mice. This is the first report that larvae hatched from T. canis embryonated eggs maintained for a long time can cause murine ocular toxocariasis. These results further extend our knowledge of the pathogenicity of T. canis embryonated eggs

Seroprevalence of Toxoplasma Gondii Infection among Pre-Schoolchildren Aged 1-5 Years in the Democratic Republic of Sao Tome and Principe, Western Africa

The prevalence status of Toxoplasma gondii infection in children of the Democratic Republic of Sao Tome and Principe (DRSTP), Western Africa, is unknown to date. A serologic survey of T gondii infection among pre- schoolchildren aged = 2 years (82.61 %; 19/23) had high LA titres of >= 1:1024, indirectly indicating acute Toxoplasma infection. This study is the first report indicating that T gondii infection is not low in pre- schoolchildren aged < 5 years in the DRSTP. Whether the DRSTP pre-schoolchildren acquire T gondii infection through constant exposure to the parasite from their daily activities owing to poor environmental hygiene should be further evaluated. (c) 2005 Royal Society of Tropical Medicine and Hygiene. Published by Elsevier Ltd. All rights reserved

Seroprevalence of Toxoplasma Gondii Infection among Inhabitants in the Democratic Republic of Sao Tome and Principe

The level of Toxoplasma gondii infection among the general population of the Democratic Republic of Sao Tome and Principe is unclear. The T gondii infection status of inhabitants who visited National Central Hospital on Sao Tome Island was assessed by a latex agglutination test. The overall seroprevalence was 74.5% (120/161). No significant gender difference in seroprevalence was found between mates and females. The older age group ( :45 years) had significantly higher seroprevalence (80.0%, 28/35) than the younger age group (05 years) (20.0%, 3/15) (x(2) = 16.04, P< 0.001). (C) 2007 Royal Society of Tropical Medicine and Hygiene. Published by Elsevier Ltd. All rights reserved