Resistance of Acanthamoeba cysts to disinfection in multiple contact lens solutions.

Acanthamoebae are free-living amoebae found in the environment, including soil, freshwater, brackish water, seawater, hot tubs, and Jacuzzis. Acanthamoeba species can cause keratitis, a painful vision-threatening infection of the cornea, and fatal granulomatous encephalitis in humans. More than 20 species of Acanthamoeba belonging to morphological groups I, II, and III distributed in 15 genotypes have been described. Among these, Acanthamoeba castellanii, A. polyphaga, and A. hatchetti are frequently identified as causing Acanthamoeba keratitis (AK). Improper contact lens care and contact with nonsterile water while wearing contact lenses are known risk factors for AK. During a recent multistate outbreak, AK was found to be associated with the use of Advanced Medical Optics Complete MoisturePlus multipurpose contact lens solution, which was hypothesized to have had insufficient anti-Acanthamoeba activity. As part of the investigation of that outbreak, we compared the efficacies of 11 different contact lens solutions against cysts of A. castellanii, A. polyphaga, and A. hatchetti (the isolates of all species were genotype T4), which were isolated in 2007 from specimens obtained during the outbreak investigation. The data, generated with A. castellanii, A. polyphaga, and A. hatchetti cysts, suggest that the two contact lens solutions containing hydrogen peroxide were the only solutions that showed any disinfection ability, with 0% and 66% growth, respectively, being detected with A. castellanii and 0% and 33% growth, respectively, being detected with A. polyphaga. There was no statistically significant difference in disinfection efficacy between the 11 solutions for A. hatchetti.

Subtype analysis of Cryptosporidium specimens from sporadic cases in Colorado, Idaho, New Mexico, and Iowa in 2007: widespread occurrence of one Cryptosporidium hominis subtype and case history of an infection with the Cryptosporidium horse genotype.

Subtyping was conducted in late 2007 on 57 Cryptosporidium specimens from sporadic cases in Colorado, Idaho, New Mexico, and Iowa. One previously rare Cryptosporidium hominis subtype was identified in 40 cases (70%) from all four states, and the Cryptosporidium horse genotype was identified in a pet shop employee with severe clinical symptoms.

Cutaneous dirofilariasis presenting as an eyelid swelling.

Dirofilariasis is a common filarial infection occurring in domestic and wild animals as a result of arthropod bites. However, it can be transmitted to humans after mosquito bites. Here, we report a case of a 54-year-old lady who developed an unilateral eyelid swelling secondary to Dirofilaria repens.

Hospitalization and mortality among primarily nonbreastfed children during a large outbreak of diarrhea and malnutrition in Botswana, 2006.

BACKGROUND: In 2006, a pediatric diarrhea outbreak occurred in Botswana, coinciding with heavy rains. Surveillance recorded a 3 times increase in cases and a 25 fold increase in deaths between January and March. Botswana has high HIV prevalence among pregnant women (33.4% in 2005), and an estimated 35% of all infants under the age of 6 months are not breastfed. METHODS: We followed all children <5 years old with diarrhea in the country's second largest referral hospital at the peak of the outbreak by chart review, interviewed mothers, and conducted laboratory testing for HIV and enteric pathogens. RESULTS: Of 153 hospitalized children with diarrhea, 97% were <2 years old; 88% of these were not breastfeeding. HIV was diagnosed in 18% of children and 64% of mothers. Cryptosporidium and enteropathogenic Escherichia coli were common; many children had multiple pathogens. Severe acute malnutrition (kwashiorkor or marasmus) developed in 38 (25%) patients, and 33 (22%) died. Kwashiorkor increased risk for death (relative risk 2.0; P = 0.05); only one breastfeeding child died. Many children who died had been undersupplied with formula. CONCLUSIONS: Most of the severe morbidity and mortality in this outbreak occurred in children who were HIV negative and not breastfed. Feeding and nutritional factors were the most important determinants of severe illness and death. Breastfeeding is critical to infant survival in the developing world, and support for breastfeeding among HIV-negative women, and HIV-positive women who cannot formula feed safely, may prevent further high-mortality outbreaks.

Evaluation of the impact of overseas pre-departure treatment for infection with intestinal parasites among Montagnard refugees migrating from Cambodia to North Carolina.

We evaluated the effectiveness of an overseas pre-departure regimen of five days of albendazole for presumptive treatment of intestinal parasites by examining stool specimens in treated and untreated Montagnard refugees after arrival in the United States. Among 815 refugees evaluated, fully treated refugees had a significantly lower prevalence of helminths (11 [1.4%] of 777), specifically hookworm and Ascaris lumbricoides, than untreated pregnant women (3 [20%] of 15) (P < 0.001). Multivariate analysis showed that treatment was associated with significantly lower rates of infection with helminths but not protozoa. Post-arrival gastrointestinal symptoms were not associated with findings on stool examination. Our evaluation suggests that although additional studies are needed to determine optimal treatment regimens for intestinal parasites, especially among young children and pregnant women, a five-day course of pre-departure albendazole was effective in reducing helminthic infection in treated refugees.

Rapid microsphere assay for identification of cryptosporidium hominis and cryptosporidium parvum in stool and environmental samples.

Cryptosporidium hominis and Cryptosporidium parvum are associated with massive disease outbreaks worldwide. Because these two species have different transmission cycles, identification of these parasites to the species level in clinical samples may provide laboratory data of crucial importance in epidemiologic investigations. To date, the most reliable way to differentiate C. hominis and C. parvum is based on DNA sequencing analysis of PCR amplicons. Although this approach is very effective for differentiation of Cryptosporidium species, it is labor-intensive and time-consuming compared with methods that do not require DNA sequencing analysis as an additional step and that have been successfully used for specific identification of a number of pathogens. In this study, we describe a novel Luminex-based assay that can differentiate C. hominis from C. parvum in a rapid and cost-effective manner. The assay was validated by testing a total of 143 DNA samples extracted from clinical specimens, environmental samples, or samples artificially spiked with Cryptosporidium oocysts. As few as 10 oocysts per 300 microl of stools could be detected with this assay. The assay format includes species-specific probes linked to carboxylated Luminex microspheres that hybridize to a Cryptosporidium microsatellite-2 region (ML-2) where C. hominis and C. parvum differ by one nucleotide substitution. The assay proved to be 100% specific when samples that had been characterized by direct fluorescent antibody test (DFA) and DNA sequencing analysis were tested. In addition, the assay was more sensitive than DFA and provided species identification, which is an advantage for epidemiologic studies.

PCR as a confirmatory technique for laboratory diagnosis of malaria.

We compared a nested PCR assay and microscopic examination of Giemsa-stained blood films for detection and identification of Plasmodium spp. in blood specimens. PCR was more sensitive than microscopy and capable of identifying malaria parasites at the species level when microscopy was equivocal.

Evaluation of three commercial assays for detection of Giardia and Cryptosporidium organisms in fecal specimens.

There is an increasing demand for diagnostic testing for Giardia intestinalis (G. lamblia) and Cryptosporidium parvum, with a priority being placed on obtaining diagnostic results in an efficient and timely manner. Several commercial companies have developed rapid diagnostic tests that are simple to perform and can be completed in less time than traditional methods for detecting Giardia and Cryptosporidium: We compared one of these rapid tests, the ImmunoCard STAT! (Meridian Bioscience, Inc.) lateral-flow immunoassay, with the MERIFLUOR direct fluorescent-antibody (DFA) test, the ProSpecT EZ microplate assay for Giardia and the ProSpecT microplate assay for Cryptosporidium, and modified Kinyoun's acid-fast stained smears for the detection of Cryptosporidium using 246 specimens. The MERIFLUOR DFA (Meridian Bioscience, Inc.) test detected the largest number of cases (32 Giardia and 37 Cryptosporidium) infections and was used to calculate the sensitivity and specificity of the other tests. For Giardia, the sensitivities of the ImmunoCard STAT! and the ProSpecT Giardia EZ microplate assay (Alexon-Trend, Inc.) were 81 and 91%, respectively. For detection of Cryptosporidium, the sensitivities of the ImmunoCard STAT!, the ProSpecT Cryptosporidium microplate assay (Alexon-Trend, Inc.), and modified Kinyoun's acid-fast stained smears were 68, 70, and 78%, respectively. Test specificities were equal to or greater than 99%. Specimens with very small numbers of organisms were not detected by the ImmunoCard STAT!, the ProSpecT microplate assay or modified Kinyoun's acid-fast stained smears.

Baylisascaris procyonis in the metropolitan Atlanta area.

Baylisascaris procyonis, the raccoon roundworm responsible for fatal larva migrans in humans, has long been thought to be absent from many regions in the southeastern United States. During spring 2002, 11 (22%) of 50 raccoons trapped in DeKalb County, Georgia, had B. procyonis infection. The increasing number of cases highlight this emerging zoonotic infection.