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A comprehensive field study was carried out with the following objectives: (a) to assess the usefulness of individual and bulk tank milk analysis for determining Neospora caninum serostatus in individual cows and herds, and (b) to study the associations between N. caninum infection status (based on milk testing), and several productive and reproductive parameters in the animals. Antibodies were detected with a commercially available ELISA test (Bio K 192/5). Analysis of paired serum and milk samples from 1134 lactating cows on 38 farms revealed that 97.6% of the ELISA results were coincident, irrespective of whether serum or milk samples were used. Moreover, multiple linear regression analysis revealed that 86.0% of the variations in ELISA values in milk were due to variations in the serum. The measurement of antibodies in bulk tank milk was a good estimator of the herd level status of N. caninum infection, and enabled detection of infection in 94.7% herds with ≥10.0% seropositive cows and/or in all herds with >4% highly seropositive cows. The odds ratio for abortion in seropositive animals was 9.1 times higher than in seronegative animals. The infection serostatus was also a significant risk factor, as the odds ratio for abortion was even higher (12.0 times) in cows categorized as highly seropositive. ELISA values for the bulk milk from 387 randomly selected herds were negatively associated with average milk production. Moreover, milk production losses mainly occurred on farms categorized as highly positive (i.e. herds with ≥20.0% seropositive cows)., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Ocular toxoplasmosis can result in recurrent uveitis. Studies have shown that a correlation between active ocular toxoplasmosis and the presence of anti-Toxoplasma gondii secretory IgA (SIgA) in tears. This study compares anti-T. gondii SIgA levels in patients' tears during the acute and inactive phases of toxoplasmic uveitis. Twenty-nine positive tear specific SIgA for T. gondii patients with acute toxoplasmic uveitis were selected and were followed-up for at least two years, when the anti-T. gondii SIgA tears levels were determined. Specific SIgA for T. gondii was negative in 22 patients (75.86%) and positive in seven patients (24.13%) of whom six (85.7%) were followed over three years. Average SIgA levels during the acute phase are 1.54 and decrease significantly to 0.72 (p = 0.0001) during the inactive phase of disease. Because anti-T. gondii SIgA in the tear is negative in 75.86% of patients after the acute phase of infection, T. gondii SIgA levels may be used as a complementary diagnostic marker for active ocular toxoplasmosis.

We examined by parasitological tests (hemocultures and buffy coat) infection by Trypanosoma cruzi and T. evansi in blood samples from Leopardus pardalis, Cerdocyon thous and domestic dogs. Besides, 25 T. cruzi isolates previously derived from feral pigs and small wild mammals were here characterized by miniexon gene and demonstrated to be in the TcI genotype. Herein, we make an overall analysis of the transmission cycle of both trypanosome species in the light of the assemblage of data collected over the last seven years. The carnivore Nasua nasua was confirmed to play a major role in the transmission cycles of both T. cruzi and T. evansi since it was the species that had the higher prevalence and higher parasitemias by both flagellate species. In addition, our results show that both trypanosomatid species may be found throughout the Pantanal landscape, in all forest strata, as shown by the infection of carnivore, arboreal and terrestrial scansorial marsupial species in complex and seasonal transmission cycles. We propose that transmission of T. cruzi and T. evansi in the southern Pantanal region takes place via an intricate ecological trophic network involving generalist and specialist mammal species that are linked through a robust food-web connection., (Copyright © 2011 Royal Society of Tropical Medicine and Hygiene. Published by Elsevier Ltd. All rights reserved.)

This prospective study evaluated the value of laboratorial diagnosis in ocular toxoplasmosis analyzing peripheral blood samples from a group of Brazilian patients by immunologic and molecular methods. We analyzed blood samples from 184 immunocompetent patients with ocular disorders divided into 2 groups: Group I, composed of samples from 49 patients with ocular toxoplasmosis diagnosed by clinical features; Group II, samples from 135 patients with other ocular diseases. Samples were assayed by conventional polymerase chain reaction (cnPCR), real-time PCR (qPCR) for Toxoplasma gondii, indirect immunofluorescence reaction (IF), avidity test (crude tachyzoite lysate as antigen), and excreted-secreted tachyzoite proteins as antigen (ESA-ELISA). cnPCR and qPCR profiles were concordant in all samples. Positive PCR was shown in 40.8% of group I patients. The majority of the positive blood samples (75%) were taken from patients with toxoplasmic retinochoroiditis scars, and the others (25%), from patients with retinal exudative lesions. Despite that 86 of the 135 patients from Group II had asymptomatic toxoplasmosis, all DNA blood samples had negative PCR. Concordant results were shown in the data obtained by serologic methods. Around 24% of the patients with ocular toxoplasmosis had high antibody titers determined by ESA-ELISA and IF. Anti-ESA antibodies are shown principally in patients with active infection. Collectively, these data demonstrate the presence of tachyzoites in the blood of patients with chronic infection, supporting the idea of recurrent disease. Circulating parasites in blood of immunocompetent individuals may be associated with the reactivation of the ocular disease., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Background: In recent years, the protozoan Tritrichomonas foetus has been recognised as an important cause of chronic large-bowel diarrhoea in purebred cats in many countries, including Norway. The aim of this cross-sectional study was to determine the proportion of animals with T. foetus infection among clinically healthy cats in Norway and to assess different risk factors for T. foetus infection, such as age, sex, former history of gastrointestinal symptoms and concurrent infections with Giardia duodenalis and Cryptosporidium sp., Methods: The sample population consisted of 52 cats participating in three cat shows in Norway in 2009. Samples were examined for motile T. foetus by microscopy, after culturing and for T. foetus-DNA by species-specific nested PCR, as well as for Giardia cysts and Cryptosporidium oocysts by immunofluorescent antibody test (IFAT)., Results: By PCR, T. foetus-DNA was demonstrated in the faeces of 11 (21%) of the 52 cats tested. DNA-sequencing of five positive samples yielded 100% identity with previous isolates of T. foetus from cats. Only one sample was positive for T. foetus by microscopy. By IFAT, four samples were positive for Giardia cysts and one for Cryptosporidium oocysts, none of which was co-infected with T. foetus. No significant associations were found between the presence of T. foetus and the various risk factors examined., Conclusions: T. foetus was found to be a common parasite in clinically healthy cats in Norway.

Background: In formerly endemic areas where malaria transmission has declined, levels of population immunity to Plasmodium falciparum provide information on continued malaria transmission and potentially susceptible populations. Traditional techniques for measuring serological responses to P. falciparum antigens use plasma or dried blood spots (DBS). These invasive procedures pose a biohazard and may be unacceptable to communities if performed frequently. The use of oral fluid (OF) samples to detect antibodies to P. falciparum antigens may be a more acceptable strategy to monitor changes in population immunity., Methods: An enzyme immunoassay was optimized to detect antibodies to whole, asexual stage P. falciparum antigens. Optical density (OD) values from paired DBS and OF samples collected as part of a community-based survey of malaria parasitaemia were compared., Results: Oral fluid and dried blood spot samples were collected from 53 participants in Southern Province, Zambia. Their ages ranged from 1 to 80 years and 45% were female. A statistically significant correlation (r=0.79; P<0.01) was observed between OD values from OF and DBS samples. The OF assay identified all DBS-confirmed positive and negative samples, resulting in 100% sensitivity and specificity., Conclusions: Oral fluid is a valid alternative specimen for monitoring changes in antibodies to P. falciparum antigens. As OF collection is often more acceptable to communities, poses less of a biohazard than blood samples and can be performed by community volunteers, serological surveys using OF samples provide a strategy for monitoring population immunity in regions of declining malaria transmission.

Whereas Leishmania infantum, the agent of visceral leishmaniasis (VL), is well known in North Africa, very limited data exist on its spread in West Africa, where mainly cutaneous leishmaniasis has been widely reported. Nevertheless, dogs infected with L. infantum were recently found in the Mont Rolland District in Senegal. To provide a better understanding of L. infantum epidemiology in this area, clinical and serological surveys were carried out to determine the seroprevalence of L. infantum-specific antibodies in the human population. In parallel, an analysis of environmental and individual factors associated with Leishmania antigen seropositivity was conducted to identify potential risk factors for exposure. Although no cases of VL were detected within this study, a large part of the population (73/315; 23%) was exposed to infection, with a strong age effect (being >40 years old increased the risk of being seropositive). Moreover, the presence of Nebedaye trees (Moringa oleifera) and infected dogs in the household were factors increasing the risk of exposure in household members. These results may provide important information to identify the still unknown sandfly species involved in transmission., (Copyright © 2011 Royal Society of Tropical Medicine and Hygiene. Published by Elsevier Ltd. All rights reserved.)

Background: Antibody responses to malaria antigens reflect exposure to parasites, and seroprevalence correlates with malaria transmission intensity. Antibodies are routinely measured in sera or on dried blood spots but a non-invasive method would provide extra utility in sampling general populations. Saliva is already in use in the detection of plasma-derived IgM and IgG to viral infections. In this study, antibodies to Plasmodium falciparum merozoite antigens were compared between blood and saliva samples from the same individuals in unlinked surveys conducted in Tanzania and The Gambia., Methods: In Tanzania, 53 individuals provided paired fingerprick blood and saliva sample using two commercially available sampling devices. In the Gambia, archived plasma and saliva samples collected from 200 children in the Farafenni area in a cross-sectional survey were analyzed.IgG antibodies against P. falciparum antigens, Merozoite Surface Protein-1 (MSP-119) and Apical membrane Antigen (AMA-1) were measured by ELISA in paired saliva and blood samples from both sites. Antibody levels were compared as continuous optical density (OD) values and by sero-positivity., Results: Significant correlations between saliva and plasma antibody levels were seen in Tanzania for both antigens, AMA-1(r2 range 0.93 to 0.89, p < 0.001) and MSP-119 (r2 range 0.93 to 0.75, p < 0.001), with a weaker correlation for results from The Gambia (r2range 0.64 to 0.63, p < 0.01). When assessed as seropositivity and compared with plasma, sensitivity and specificity were good with saliva antibody levels to both AMA-1 and MSP-1(19) (sensitivity range 64-77% and specificity range 91-100% & 47-67% and 90-97% respectively) over the different sample sets., Conclusions: These data demonstrate anti-malarial antibodies can be detected in saliva and correlate strongly with levels in plasma. This non-invasive relatively simple collection method will be potentially useful for general population surveys, and particularly in migratory populations or those with infrequent contact with health services or opposed to blood withdrawal. Further studies will be needed to optimize collection methods, standardize volumes and content and develop controls.

Over a 2-yr study period, we investigated possible endogenous transplacental transmission of Neospora hughesi in 74 mare and foal pairs following the diagnosis of neuronal neosporosis in a weanling foal. Presuckle and postsuckle serum of each foal, serum and colostrum of each periparturient mare, and serum of each mare and foal pair, collected at 3-mo intervals thereafter, were tested for N. hughesi using an indirect fluorescent antibody test (IFAT). Furthermore, whole blood and colostrum samples and placentae were tested for the presence of N. hughesi by real-time PCR. The mares' seroprevalence at foaling based on IFAT (titer ≥ 160) was 52 and 6% in 2006 and 2007, respectively. Colostral antibodies against N. hughesi were detected in 96 and 11% of the mares in the 2-yr study. With the exception of 3 foals, all remaining foals were born seronegative to N. hughesi. Passive transfer of colostral antibodies to N. hughesi was documented in 15 foals. Three foals born from 2 different mares had presuckle antibodies at a titer ranging from 2,560 to 20,480. All 3 foals were born healthy. Two foals were born to the same dam that also gave birth to the weanling diagnosed with neuronal neosporosis in 2005. The third foal was born to a second mare with no previous foaling history at the farm. Seroconversion was documented in 10 foals and 9 mares over the 2-yr study. All blood and colostrum samples tested PCR negative for N. hughesi. Only 1 placenta collected in 2007 from the mare with the 2 congenitally infected foals tested PCR positive for N. hughesi. In conclusion, N. hughesi persisted in this population via endogenous transplacental infection.

Amoebic liver abscess is a common disease, especially in endemic areas, but it is a rare cause of inferior vena cava (IVC) obstruction, with only a few cases appearing in the literature. We report three cases of amoebic liver abscess complicated with obstruction of the IVC and which responded to conservative treatment or radiological intervention.

The aim of this study was to determine the congenital infection by Neospora caninum in the water buffalo (Bubalus bubalis), a natural intermediate host. Nine pregnant water buffalos, raised under free-grazing condition, were slaughtered, and their fetuses were collected. Samples of brain and thoracic fluid were obtained from those fetuses, with gestational ages ranging from 2 to 5 months. The DNA of N. caninum was detected and identified in the brain of one of those fetuses, using two PCR assays, one directed to the Nc5 gene and the other, to the common toxoplasmatiid ITS1 sequence. The DNA fragments produced on PCR were sequenced, and N. caninum was confirmed in the samples. No antibodies to N. caninum were detected on any sample of thoracic fluid by immunofluorescent antibody test (IFAT < 25). This is the first confirmation of congenital transmission of N. caninum in water buffalos.

The aim of this study was to analyze the presence of 62 kDa proteinase and anti-62 kDa proteinase antibody in clinical samples of symptomatic and asymptomatic infected women. Proteinase was detected in all the swabs vaginal of infected women. Significantly, amounts of antigen (mean optical density (OD) values) were detected in swabs vaginal of symptomatic as compared to asymptomatic women. This protein was not detected in the group of patients with Trichomonas vaginalis-culture-negative results and in the groups of samples infected with other agents. Antibody to 62 kDa was detected in the swabs vaginal the only 66.6% of the symptomatic and 55.5% of the asymptomatic infected women. Antibody to 62 kDa was also detected in 7/30 of the swabs vaginal from uninfected women. No significant difference was observed in mean OD values of vaginal swabs of T. vaginalis-infected symptomatic as compared to asymptomatic women. The presence of proteinase in 100% of T. vaginalis-infected women suggested that 62 kDa proteinase could be a virulence factor.

Toxoplasmosis is a common congenital infection. It does not usually produce recognizable signs of infection at birth so most infected newborns are not detected by routine clinical examination and remain untreated. Infected children without clinical symptoms should nonetheless be identified and treated as early as possible. Serological diagnosis of congenital toxoplasmosis is quite difficult. The aim of this study was to evaluate the utility of Western blot for the diagnosis of congenital toxoplasmosis. We compared the immunological profiles of mothers and children to differentiate between passively transmitted maternal antibodies and antibodies synthesized by the infants in the first three months of life. The method enabled us to diagnose congenital toxoplasmosis in cases in which the infection had not been detected by classical serology techniques.

Toxoplasmosis after solid organ transplantation is a complication associated with high morbidity and mortality. Universal prophylaxis with trimethoprim-sulfamethoxazole (TMP-SMX) is effective to prevent post-transplant toxoplasmosis. We report two cases of renal transplant recipients with negative antibodies against Toxoplasma gondii pretransplant who developed toxoplasmosis after TMP-SMX discontinuation. We have also performed a review of published cases of primary toxoplasmosis after renal transplantation. Of 20 cases reviewed, 11 were male and the mean age was 37.8 years (SD = 13.8). Donor serology for T. gondii was determined in 15 donors, two of them (13%) with negative immunoglobulin (Ig)G and four (27%) with positive IgG and IgM antibodies. Fever was present in 85% of primary toxoplasmosis and hematologic abnormalities were observed in 69% of the cases. Ten patients died (50%). All patients with fatal outcomes had clinical evidence of toxoplasmosis during the early post-transplant period (first 90 days), while no patient with late toxoplasmosis died (P = 0.003). Primary toxoplasmosis is associated with high mortality rates and TMP-SMX prophylaxis can delay the onset of symptoms resulting in an improvement of prognosis., (© 2010 The Authors. Transplant International © 2010 European Society for Organ Transplantation.)

Toxoplasma gondii, Bartonella henselae and feline herpesvirus-1 (FHV-1) have been implicated as causative agents in feline uveitis. The usefulness of serum and aqueous humor (AH) antibody testing for these agents is limited as antibodies can be detected in both healthy cats and cats with uveitis. Very few studies using polymerase chain reaction (PCR) assays to amplify organism DNA from samples from cats with uveitis have been performed. In this study, assays to detect T gondii antibodies, feline leukemia virus antigen, feline immunodeficiency virus antibody, and Bartonella species antibodies were performed on serum and PCR assays for amplification of T gondii, Bartonella species, and FHV-1 DNA were performed on blood and AH samples from 104 cats with endogenous uveitis and 19 healthy cats. Results suggest the addition of the PCR assay to the diagnostic work-up for cats with uveitis will increase the detection of T gondii and FHV-1; however, the diagnostic usefulness of these additional data is not clear., (Copyright © 2010 ISFM and AAFP. Published by Elsevier Ltd. All rights reserved.)

Background: The RTS,S/AS02(D) vaccine has been shown to have a promising safety profile, to be immunogenic and to confer protection against malaria in children and infants., Methods and Findings: We did a randomized, controlled, phase I/IIb trial of RTS,S/AS02(D) given at 10, 14 and 18 weeks of age staggered with routine immunization vaccines in 214 Mozambican infants. The study was double-blind until the young child completed 6 months of follow-up over which period vaccine efficacy against new Plasmodium falciparum infections was estimated at 65.9% (95% CI 42.6-79.8, p<0.0001). We now report safety, immunogenicity and estimated efficacy against clinical malaria up to 14 months after study start. Vaccine efficacy was assessed using Cox regression models. The frequency of serious adverse events was 32.7% in the RTS,S/AS02(D) and 31.8% in the control group. The geometric mean titers of anti-circumsporozoite antibodies declined from 199.9 to 7.3 EU/mL from one to 12 months post dose three of RTS,S/AS02(D), remaining 15-fold higher than in the control group. Vaccine efficacy against clinical malaria was 33% (95% CI: -4.3-56.9, p = 0.076) over 14 months of follow-up. The hazard rate of disease per 2-fold increase in anti-CS titters was reduced by 84% (95% CI 35.1-88.2, p = 0.003)., Conclusion: The RTS,S/AS02(D) malaria vaccine administered to young infants has a good safety profile and remains efficacious over 14 months. A strong association between anti-CS antibodies and risk of clinical malaria has been described for the first time. The results also suggest a decrease of both anti-CS antibodies and vaccine efficacy over time., Trial Registration: ClinicalTrials.gov NCT00197028.

Visceral leishmaniasis (VL) is an important vector-borne disease caused by Leishmania donovani in the Indian subcontinent. The actual incidence and role of asymptomatic infections in the region are not wellknown. We used the direct agglutination test (DAT) and the rK39 ELISA as L. donovani infection markers in 10 VL endemic villages in Nepal. DAT titre distribution showed two subgroups in the population (infected and non-infected individuals), while rK39 did not. The agreement between both tests was moderate (j = 0.53; 95% CI 0.49–0.57). More research is needed to develop validated markers for Leishmania infection.

In a cross-sectional study to determine the seroprevalence of, and possible risk factors for, Toxoplasma gondii infection in the pregnant women of Saudi Arabia, all of the pregnant Saudi women attending the Al Ahsa Maternity Hospital over a 1-year period were invited to participate. In an interview with each subject, the relevant socio-demographic data and information on housing conditions, previous obstetric history and possible risk factors for Toxoplasma infection (e.g.frequency of consumption of undercooked meat, unwashed raw vegetables and/or unwashed raw fruit, contact with soil, and main sources of drinking water) were collected. Each subject was then checked for anti-Toxoplasma gondii IgG and IgM in commercial ELISA. Of the 554 expectant women investigated, 51.4% were found seropositive for anti-Toxoplasma IgG (indicating chronic infection) and 8.8% for anti-Toxoplasma IgM (indicating acute infection), with 6.1% of the women seropositive for Toxoplasma -specific IgM but seronegative for Toxoplasma-specific IgG. Acute infection was most common among the women who were relatively young, lived in rural areas and had relatively low incomes. The results of a multivariate logistic regression indicated that the significant positive predictors for chronic Toxoplasma infection were increasing age, rural residence, low family income, frequent consumption of undercooked meat, and previous obstetric problems (and/or multiparity). Although of questionable accuracy, the results of the present study revealed a relatively high seroprevalence of (possibly primary) acute Toxoplasma infection in the pregnant women, with the potential for transmission of the parasite to the foetuses.

Protein kinase C-theta (PKC-theta) is important for the activation of autoreactive T cells but is thought to be of minor importance for T-cell responses in infectious diseases, suggesting that PKC-theta may be a target for the treatment of T-cell-mediated autoimmune diseases. To explore the function of PKC-theta in a chronic persisting infection in which T cells are crucial for pathogen control, we infected BALB/c PKC-theta(-/-) and PKC-theta(+/+) wild-type mice with Toxoplasma gondii. The PKC-theta(-/-) mice succumbed to necrotizing Toxoplasma encephalitis due to an insufficient parasite control up to day 40, whereas the wild-type mice survived. The number of T. gondii-specific CD4 and CD8 T cells was significantly reduced in the PKC-theta(-/-) mice, resulting in the impaired production of protective cytokines (gamma interferon, tumor necrosis factor) and antiparasitic effector molecules (inducible nitric oxide, gamma interferon-induced GTPase) in the spleen and brain. In addition, Th2-cell numbers were reduced in infected the PKC-theta(-/-) mice, paralleled by the diminished GATA3 expression of PKC-theta(-/-) CD4 T cells and reduced T. gondii-specific IgG production in serum and cerebrospinal fluid. Western blot analysis of splenic CD4 and CD8 T cells revealed an impaired activation of the NF-kappaB, AP-1, and MAPK pathways in T. gondii-infected PKC-theta(-/-) mice. Adoptive transfer of wild-type CD4 plus CD8 T cells significantly protected PKC-theta(-/-) mice from death by increasing the numbers of gamma interferon-producing T. gondii-specific CD4 and CD8 T cells, illustrating a cell-autonomous, protective function of PKC-theta in T cells. These findings imply that PKC-theta inhibition drastically impairs T. gondii-specific T-cell responses with fatal consequences for intracerebral parasite control and survival.

Toxoplasmosis is an important cause of abortion and stillbirth in sheep on a worldwide basis. In the present study, the role of Toxoplasma gondii in inducing abortion in sheep of the Mashhad area of Iran was addressed using serological and parasitological methods. In total, 325 aborted ovine fetuses were collected between 2006 and 2008 during lambing season. Thoracic and abdominal fluids of aborted fetus were serologically investigated with a T. gondii -IFAT. Antibody titers equal to or greater than 1:20 were detected in 17 (5.2%) of ovine fetuses. Processed brain samples of seropositive ovine fetuses were intraperitoneally inoculated into mice for isolation of T. gondii . The process yielded a single T. gondii isolate that remained avirulant for mice after several passages. The results document that T. gondii is among the important causes of ovine abortion in Iran.

Toxoplasma gondii is one of the important zoonotic parasites of worldwide zoological & geographical distribution. ELISA prevalence of Toxoplasma gondii in Egyptian locally bred working donkeys in greater Cairo was evaluated. The donkeys were 75 females & 25 males aged between 3-10 years. The results showed that ELISA antibodies of T. gondii were found in 45 out of 100 (45%) working donkeys. Donkeys' milk obtained from fifteen pregnant females was T. gondii positive in seven (46.3%). The zoonotic role of donkeys and their milk were discussed.

Background: Plasmodium vivax is divided into two subtypes, a dominant form, VK210 and a variant form, VK247. This division is dependent on the amino acid composition of the circumsporozoite (CS) protein. In this study, the prevalence of the VK247 variant form of P. vivax was investigated in Myanmar., Methods: The existence of malaria parasites in blood samples was determined by microscopic examination, polymerase chain reaction (PCR) and DNA hybridization assays. To test for antibodies against P. vivax and Plasmodium falciparum in blood samples, an indirect immunofluorescence antibody test (IFAT) was performed using asexual blood antigens. An enzyme-linked immunosorbent assay with synthetic VK210 and VK247 antigens was carried out to discriminate between the P. vivax subtypes., Results: By thick smear examination, 73 (n=100) patients were single infected with P. vivax, one with P. falciparum and 13 with both species. By thin smear, 53 patients were single infected with P. vivax, eight with only P. falciparum and 16 with both. Most of the collected blood samples were shown to be P. vivax positive (n=95) by PCR. All cases that were positive for P. falciparum by PCR (n=43) were also positive for P. vivax. However, 52 cases were single infected with P. vivax. IFAT showed antibody titres from 1:32 to 1:4,096. Additionally, using specific antibodies for VK210 and VK247, ELISA showed that 12 patients had antibodies for only the VK210 subtype, 4 patients had only VK247 subtype antibodies and 21 patients had antibodies for both subtypes. Using a DNA hybridization test, 47 patients were infected with the VK210 type, one patient was infected with VK247 and 23 patients were infected with both subtypes., Conclusions: The proportion of the VK247 subtype in Myanmar was 43.1% (n=25) among 58 positive cases by serodiagnosis and 25.6% (n=24) among 94 positive cases by genetic diagnosis. In both diagnostic methods, the infection status of malaria patients is highly diverse with respect to malaria species, and multiple clonal infections are prevalent in Myanmar. Therefore, the complexity of the infection should be considered carefully when diagnosing malaria in Myanmar.

The Brazilian Ministry of Health recommends the culling and euthanasia of dogs with a positive serological test for canine visceral leishmaniasis (CVL). In the Municipality of Rio de Janeiro, the technique used for the diagnosis of CVL is the indirect fluorescent antibody test (IFAT), using blood samples eluted on filter paper (eluate). A dog survey was conducted over a period of one year in the region of Carapiá, in order to evaluate the diagnosis of CVL in this region. All animals underwent clinical examination, and blood samples (serum and eluate) were collected for analysis by enzyme immunoassay (ELISA) and IFAT. A skin biopsy was obtained for parasitological examination (culture). A total of 305 animals were studied and Leishmania chagasi was isolated from nine animals. Sensitivity and specificity were 100% and 96.6% for ELISA, respectively, 100% and 65.5% for IFAT (cut-off at a 1:40 dilution), 100% and 83.4% for IFAT (cut-off at a 1:80 dilution), and 22.2% and 97.0% for eluate IFAT. In conclusion, ELISA was the best tool for the diagnosis of CVL among the serological techniques tested. The present results suggest the need for a better evaluation of filter paper IFAT as the only diagnostic method for CVL in the Municipality of Rio de Janeiro.

The present study was conducted to determine the prevalence and incidence of trypanosomosis and to investigate some factors influencing them in an agro-pastoral area of southwestern Burkina Faso. A total of 363 crossbred cattle (Baoule-zebu peul), which were bred under natural trypanosomosis challenge, were monitored monthly for parasitaemia, packed cell volume (PCV) and serological analyses over 2years. The parasitological prevalence estimated at the beginning of the survey using the buffy coat technique (BCT) was 7.54%. As much as 66.7% of all trypanosome infections were due to Trypanosoma vivax, 23.8% due to Trypanosoma congolense and 9.5% due to T. vivax/T. congolense mixed infections. The monthly serological incidence varied from 0.29% to 19.29%. The season was the most important factor influencing the serological prevalence and incidence and the animal PCV. The dry hot season is associated with increasing seroprevalences and incidences and consequently a decreasing average of PCV. In addition, an important spatial heterogeneity was observed., (Copyright 2009 Elsevier Ltd. All rights reserved.)

Two human single chain variable fragment (scFv) libraries were used to select clones that bound to the surface glycoprotein S16 of Cryptosporidium parvum. Panning of the Tomlinson libraries I and J resulted in the isolation of nine distinct clones. Of the four clones which had full-length scFv, three contained stop codons. The remaining five clones were truncated, with four missing the heavy chain, and one missing most of the light chain. The full-length clones exhibited better binding to native C. parvum proteins and recombinant S16 than the truncated clones, with the exception of one truncated clone. None of the selected clones cross-reacted with Giardia lamblia, Escherichia coli, Streptococcus pyogenes, Listeria monocytogenes, Bacillus cereus or another immunogenic target of C. parvum, P23. Clones expressed as the soluble scFv-gIIIp construct were able to detect C. parvum native proteins and sporozoites. Panning from naïve libraries was an useful method for isolation and identification of recombinant antibodies that have the potential for use in pathogen detection and immunotherapy., (Copyright (c) 2010 Elsevier Inc. All rights reserved.)

Background: Serological data suggest that Cryptosporidium infections are common but underreported. The invasiveness of blood sampling limits the application of serology in epidemiological surveillance. We pilot-tested a non-invasive salivary anti-Cryptosporidium antibody assay in a community survey involving children and adults., Materials and Methods: Families with children were recruited in a Massachusetts community in July; symptoms data were collected at 3 monthly follow-up mail surveys. One saliva sample per person (n = 349) was collected via mail, with the last survey in October. Samples were analyzed for IgG and IgA responses to a recombinant C. hominis gp15 sporozoite protein using a time-resolved fluorometric immunoassay. Log-transformed assay results were regressed on age using penalized B-splines to account for the strong age-dependence of antibody reactions. Positive responses were defined as fluorescence values above the upper 99% prediction limit., Results: Forty-seven (13.5%) individuals had diarrhea without concurrent respiratory symptoms during the 3-month-long follow-up; eight of them had these symptoms during the month prior to saliva sampling. Two individuals had positive IgG responses: an adult who had diarrhea during the prior month and a child who had episodes of diarrhea during each survey month (Fisher's exact test for an association between diarrhea and IgG response: p = 0.0005 for symptoms during the prior month and p = 0.02 for symptoms during the entire follow-up period). The child also had a positive IgA response, along with two asymptomatic individuals (an association between diarrhea and IgA was not significant)., Conclusion: These results suggest that the salivary IgG specific to Cryptosporidium antigens warrants further evaluation as a potential indicator of recent infections.

The current method for detecting the waterborne parasite Giardia lamblia is tedious and requires a preconcentration step. We show for the first time a piezoelectric-excited millimeter-sized cantilever (PEMC) biosensor immobilized with a monoclonal antibody against G. lamblia that exhibits selective and sensitive detection of G. lamblia cysts in several water matrixes (buffer, tap, and river water) at a detection limit of 1-10 cysts/mL without a preconcentration step. The PEMC sensor is a resonance-based device that functions at a high-order mode near 1 MHz. The antibody-immobilized sensor was exposed to 1-10,000 G. lamblia cysts/mL samples in a flow arrangement. When the cysts bind to the antibody on the sensor, the resonant frequency of the cantilever sensor decreases and is recorded continuously. Positive confirmation of sensor detection responses was obtained by environmental scanning electron microscope of sensor surface after detection experiments. Higher sample flow rates (0.5-5.0 mL/min) gave higher sensor detection response. Detecting as few as 10 cysts per mL was achieved in all three water matrixes tested, and significant sensor response was obtained in 15 min. We also show the feasibility of analyzing at a low concentration of 1 cyst/mL in a one liter sample at a high flow rate of 5 mL/min.

Aim: Comparative assessment of effectiveness of serologic methods for toxoplasmosis diagnostics in patients with HIV-infection., Materials and Methods: Sera and CSF samples from 166 patients with AIDS stage IIIB were tested for antibodies to Toxoplasma gondii by indirect immunofluorescence, ELISA and immunoblotting. Results of serological tests were compared with clinical, pathological data as well as with results of MRI and PCR., Results: Clinical value of IgG detection in blood and CSF by ELISA was shown--high level of antibodies marked reactivation of the invasion. IgG antibodies in CSF were detected only if high levels of IgG were present in the blood. Detection of antigenic determinants with molecular mass 18 - 20 and 65 - 70 kDa in immunoblotting was proposed as a criterion of cerebral toxoplasmosis reactivation., Conclusion: Complex laboratory serologic tests along with data obtained by MRI, PCR and microscopy of T. gondii cysts enhances the effectiveness of toxoplasmosis diagnostics. Knowledge of toxoplasmosis reactivation criteria in patients with AIDS will allow to develop the optimal protocol of toxoplasmosis diagnostics and substantiate measures for its prevention.

The course of coccidiosis in lambs and the species of Eimeria involved were investigated in Saxony-Anhalt, Germany. A field study was conducted on three farms (conventional lamb-fattening farms) with 59 lambs. A total of 1092 faecal samples were taken during a period from about two to seven weeks after birth; the Eimeria species involved were determined in 415 of these samples and morphometrical characteristics of oocysts of 12 Eimeria spp. were recorded. Subclinical to moderate clinical coccidiosis was observed on all the farms and infections with Eimeria spp. were detected in all study lambs. 12 Eimeria species were identified on two of the farms (A and C): E. ahsata, E. bakuensis, E. crandallis, E. faurei, E. granulosa, E. intricata, E. marsica, E. ovinoidalis, E. pallida, E. parva, E. punctata and E. weybridgensis. The majority of these species were also detected on farm B, with the exception of E. granulosa, E. intricata and E. punctata. To our knowledge this is the first reported occurrence of E. punctata in Germany. Specimens with 3, 4 and 5 Eimeria spp. were the most common. E. ovinoidalis predominated in the faecal samples which underwent oocyst differentiation (> 90% positive samples on each farm). This species also accounted for the generally high oocyst counts observed. Since even subclinical coccidiosis may entail economic losses in lamb-rearing and considering the high prevalence of the pathogenic species E. ovinoidalis, appropriate monitoring of the disease in these farms is advisable.

The kinetics of antibody production against Blastocystis hominis, an emerging infectious protozoan parasite which causes intestinal disorder in humans and animals, was studied. Sera and intestinal secretions were collected from B. hominis-immunized Balb/C mice for 8 weeks. Flow cytometry was used to monitor the levels of immunoglobulins A (IgA), G (IgG), and M (IgM) from both types of biological samples. The kinetic profile derived from flow cytometry analysis revealed that IgM led the early immune action against B. hominis infection in immune sera while IgA was the predominant antibody isotype in intestinal secretions. Western blotting revealed an array of antigens recognized by both serum and intestinal secretion antibodies. Immunoreactive B. hominis soluble proteins with molecular weights ranging from 28.2 to 77.6 kDa were detected by serum antibodies and 15.1 to 117.5 kDa by secretory antibodies. These antigens may be cytoplasmic or membrane-bound as determined through indirect fluorescent antibody test. Moreover, two immunogens (39.8 and 77.6 kDa) were commonly recognized by serum antibodies, one (70.8 kDa) by secretory antibodies and two (55.0 and 56.2 kDa) by both serum and secretory antibodies, suggesting a possible target in the further understanding of B. hominis pathogenicity, discovery of virulence factors, and development of immunology-based diagnostic protocols and alternative modes of treatment.

Background: Leishmaniasis includes a spectrum of diseases caused by protozoan parasites belonging to the genus Leishmania. The disease is traditionally classified into visceral, cutaneous, or mucocutaneous leishmaniasis, depending on clinical characteristics as well as the species involved. Leishmania tropica is one of the causative agents of cutaneous leishmaniasis, with a typical incubation period of weeks to months. Observation We describe a 17-year-old Afghani girl who had lived in the United States for 4 years and who presented with a 6-month history of pretibial ulcerations, 9.1-kg weight loss, abdominal pain, splenomegaly, and extreme fatigue. Histopathologic examination and culture with isoenzyme electrophoresis speciation of her skin lesions confirmed the presence of L tropica. In addition, results of serum laboratory and serological studies were highly suggestive of concomitant visceral involvement. The patient was treated with a 28-day course of intravenous pentavalent antimonial compound sodium stibogluconate with complete resolution of her systemic signs and symptoms and improvement of her pretibial ulcerations., Conclusions: This is an exceptional case in that our patient presented with disease after an incubation period of years rather than the more typical weeks to months. In addition, this patient had confirmed cutaneous involvement, as well as strong evidence of viscerotropic disease caused by L tropica, a species that characteristically displays dermotropism, not viscerotropism.

Toxoplasma gondii causes posterior uveitis and the specific diagnosis is based on clinical criteria. The presence of anti-T. gondii secretory IgA (sIgA) antibodies in patients' tears has been reported and an association was found between ocular toxoplasmosis and the anti-T. gondii sIgA isotype in Brazilian patients. The purpose of this study was to provide an objective validation of the published ELISA test for determining the presence of anti-T. gondii sIgA in the tears of individuals with ocular toxoplasmosis. Tears from 156 patients with active posterior uveitis were analysed; 82 of them presented characteristics of ocular toxoplasmosis (standard lesion) and 74 patients presented uveitis due to other aetiologies. Cases of active posterior uveitis were considered standard when a new inflammatory focus satellite to old retinochoroidal scars was observed. The determination of anti-T. gondii sIgA was made using an ELISA test with crude tachyzoite antigenic extracts. Tears were collected without previous stimulation. Detection of sIgA showed 65.9% sensitivity (95% CI = 54.5-74.4), 71.6% specificity (95% CI = 59.8-81.2), a positive predictive value of 72% (95% CI = 60.3-81.5) and a negative predictive value of 65.4% (95% CI = 54.0-75.4). sIgA reactivity was higher in the tears of patients with active posterior uveitis due to T. gondii (p < 0.05). The test is useful for differentiating active posterior uveitis due to toxoplasmosis from uveitis caused by other diseases.

Purpose: To evaluate the incidence and clinical features of patients with ocular toxoplasmosis in a Colombian cohort., Methods: We collected prospectively the clinical features of patients with ocular toxoplasmosis seen at the 'Universidad del Quindio' health centre between September 2005 and September 2007 (24 months)., Results: Seventy patients were included in the analysis (95 affected eyes). The median age at the first episode was 21 years (range: 1-54 years). Thirty-two patients had active lesions (45.7%), one of them had active lesions in both eyes. The acquisition of infection was determined in 14 patients as congenital (20%), in seven as an acquired postnatal infection (10%), and in 49 as undetermined (70%). Bilateral involvement was found in 25 cases (35.7%). Unilateral legal blindness (<20/200) was found in 14 of 37 inactive cases (37.8%). The most frequent complication was strabismus (n: 12; 13.4%)., Conclusions: There is a high incidence of cases of ocular toxoplasmosis in Quindio region (three new episodes by 100,000 inhabitants by year). Clinical features of ocular toxoplasmosis in Colombia are similar to those reported in other regions but there are no comparative data about the size and number of lesions.

We compared the accuracy of ELISA and indirect immunofluorescence (IIF) using Leishmania braziliensis and L. major-like antigens and antigens from the Bio-Manguinhos kit for serological diagnosis of American tegumentary leishmaniasis (ATL). Cut-off values were defined by the area under the receiver-operating characteristic curve. For ELISA, statistical analyses revealed better accuracy [95.7% sensitivity, 100% specificity, 100% positive predictive value (PPV), 97.5% negative predictive value (NPV)] and reliability [intraclass correlation coefficient (ICC): 0.940] for L. braziliensis antigen compared with L. major-like antigen (78.7% sensitivity, 82.8% specificity, 73.3% PPV, 86.6% NPV, ICC: 0.833). ELISA optical density values obtained for both antigens were higher in mucosal forms of ATL. For IIF, sensitivity and specificity were 81.5 and 86.2%, respectively, for the L. braziliensis antigen, compared with 95.4 and 77.7% for the L. major-like antigen and 75.4 and 89.2% for the Bio-Manguinhos kit. No difference in the specificity of the IIF test was observed between antigens, whereas sensitivity differed between the L. braziliensis and L. major-like antigens and the Bio-Manguinhos kit. Parallel ELISA and IIF testing increased sensitivity, irrespective of the antigen employed, and serial testing increased overall specificity. These results support the recommendation that ELISA employing L. braziliensis antigen be used as a diagnostic tool for suspected cases of ATL in L. braziliensis-endemic areas.

Acanthamoeba is an opportunistic protozoan pathogen that can produce keratitis and rare but fatal encephalitis. In the present study, we examined secretory IgA antibody to Acanthamoeba castellanii of the T4 genotype in mucosal secretions from 114 individuals of 37 countries, inhabitants and/or visitors, aged 16-65 years in London, UK. Acanthamoeba antibody prevalence rate was more than 85%, without any significant differences between males (86.2%) and females (89.2%). Some epidemiological factors contributing to the high prevalence of antibody to Acanthamoeba in surveyed population are discussed further.

The protozoan Trypanosoma cruzi is the etiological agent of Chagas' disease, a major chronic infection in Latin America. Currently, there are neither effective drugs nor vaccines for the treatment or prevention of the disease. Several T. cruzi surface antigens are being tested as vaccines but none of them proved to be completely protective, probably because they represent only a limited repertoire of all the possible T. cruzi target molecules. Taking into account that the trypomastigote stage of the parasite must express genes that allow the parasite to disseminate into the tissues and invade cells, we reasoned that genes preferentially expressed in trypomastigotes represent potential targets for immunization. Here we screened an epimastigote-subtracted trypomastigote cDNA expression library by genetic immunization, in order to find new vaccine candidates for Chagas' disease. After two rounds of immunization and challenge with trypomastigotes, this approach led to the identification of a pool of 28 gene fragments that improved in vivo protection. Sequence analysis of these putative candidates revealed that 19 out of 28 (67.85%) of the genes were hypothetical proteins or unannotated T. cruzi open reading frames, which certainly would not have been identified by other methods of vaccine discovery.

In this chapter, the use of control charts to both continuously evaluate testing in individual laboratories as well as provide data for external monitoring is examined in detail. The data is based on the publication by D. E. Rebeski' et al., "Charting methods to monitor the operational performance of ELISA method for the detection of antibodies against trypanosomes" in Veterinary Parasitology, 2001, 96, 11-50, and is a detailed example of the investigation of the performance of four indirect ELISAs for the detection of antibodies against trypanosomes using Trypanosoma congolense and T. vivax antigen-precoated plates in 15 veterinary diagnostic laboratories in Africa and Europe. The study shows the practical use of charting methods with respect to assessing the operational performance of each ELISA. Data from standardized internal quality control (IQC) samples were used to assess ELISA performance indicators with reference to expected upper and lower control limits, as determined from studies by the kit producer (tentative values). Based on unprocessed (optical density) and normalized absorbance values (calculated as a percentage positivity of a control), dispersion of values from the expected data range were estimated though plotting the location and deviation of the values. In addition, assay precision was estimated by plotting the distribution of coefficients of variation <10% of the IQCs. Binding ratios of various controls were calculated to estimate the assay proficiency with respect to the accuracy of assessing whether the IQC samples tested positive or negative in the test proper. The graphical analysis of dispersion of absorbance values in combination with assay precision and proficiency criteria were considered satisfactory to allow the evaluation of the operational performances of the ELISAs, and provide useful decision-making criteria for plate acceptance and rejection. The establishment of standardized and transparent IQC data charting methods for the indirect ELISAs provided an increased measure of confidence to national laboratories with respect to their reports on disease occurrence. Moreover, the relative assay performances among all laboratories were examined, using summary data charts, with reference to the performance criteria described. The IQC data were also examined using modified Youden plot analysis, demonstrating that indirect ELISA methods can be successfully applied at diagnostic laboratories in the tropics for monitoring trypanosomosis control programs.

Apical Membrane Antigen 1 (AMA1) and Merozoite Surface Protein 1 (MSP1) were produced as a recombinant fusion protein and formulated with the adjuvant Montanide ISA 720 with the aim of replicating the structure present in the parasite protein. A previous trial with this construct demonstrated the vaccine was safe and immunogenic but was associated with injection site reactogenicity. This Phase 1a dose-escalating, double blind, randomized, controlled trial of PfCP2.9/Montanide ISA 720 was conducted to evaluate alternative dose levels and vaccination schedules, with a pre-formulated vaccine that had undergone more in-depth and frequent quality control and stability analysis. The trial was conducted in seventy healthy Chinese malaria-naïve volunteers between January 2006 and January 2007. The objective was to assess the safety, reactogenicity and immunogenicity of 5, 20 and 50microg of PfCP2.9/ISA 720 under 2 different schedules. The most common adverse event was injection site tenderness (53%). The frequency and severity of adverse events was similar in both vaccination schedules. Antibody responses were induced and remained elevated throughout the study in volunteers receiving vaccine (p<0.001). Although high antibody titers as measured by ELISA to the PfCP2.9 immunogen were observed, biological function of these antibodies was not reflected by the in vitro inhibition of parasite growth, and there was limited recognition of fixed parasites in an immunofluorescence assay. At all three dose levels and both schedules, this formulation of PfCP2.9/ISA 720 is well tolerated, safe and immunogenic; however no functional activity against the parasite was observed.

The study aimed to determine the incubation period of Babesia sp. infection in naive cattle and to monitor the serological response once exposed to natural Boophilus microplus (Rhipicephalus microplus)-infested paddocks. The study was carried out on a farm located in Veracruz, Mexico. Five groups of five steers were relocated every 3 months from a tick-free area to a tick-infested paddock. Animals were introduced in October, January, April, July, and October. Blood samples were taken daily until day 21 to determine packed cell volume (PCV), percentage of parasitized erythrocytes (PPE), and antibody titers to Babesia bigemina and B. bovis by the indirect fluorescent antibody procedure. Detection of Babesia in blood was also performed by species-specific PCR. The estimated incubation period was 6-14 days post introduction to paddocks (PIP), with fever (41 degrees C) for at least 3 days. PCV decreased by >25% and Babesia parasites were observed during the clinical phase of the disease. The highest individual PPEs (0.44% and 0.22% for B. bovis and B. bigemina, respectively) were observed from animals introduced in October. The four other groups showed a mean PPE ranging from 0.002-0.146% at day 14 PIP. All animals were detected as PCR positive between 8-14 days PIP. The highest antibody titers were 1:3328. The environmental conditions were favorable throughout the year for tick reproduction as the farm showed enzootic stability and hyperendemic conditions for bovine babesiosis. In this type of farm, strategic tick control could be accompanied by babesiosis vaccination, particularly for cattle relocated from tick-free areas.

Malaria is an infectious disease caused by plasmodium, which lives and breeds in human blood cells, and is transmitted through the bites of Anopheles mosquitoes. Renal impairment, often caused by malaria, is acute renal failure (ARF) due to acute tubular necrosis (ATN). Dengue virus is transmitted from human to human through Aedes aegypti mosquito bites. Dengue hemorrhagic fever (DHF), the most severe stage of infection, is characterized by bleeding and shock tendencies (dengue shock syndrome, DSS). ARF is a less common complication in patients with DHF, with an incidence of less than 10%. Mixed infections of two infectious agents may cause overlapping symptoms and have been reported in Africa and India. We report here a patient with ARF due to mixed infection of severe malaria and DSS. The patient presented with fever and had a history of repeated malaria infection. Physical examination revealed stable vital signs and hepatosplenomegaly. Laboratory data showed hemoconcentration, thrombocytopenia and increased serum aminotransferase. Chest X-ray showed pleural effusion. A malarial antigen and thick smear examination showed the trophozoite stage of P. falciparum. On Day 3, blood pressure dropped to 80/60 mmHg, pulse was 120 beats/minute, weak, and body temperature 36.8 C, with icterus. Other tests revealed an increase of serum urea nitrogen and creatinine levels, and serologically anti-dengue IgG antibody (+) and anti-dengue IgM antibody (-). Based on these findings, we diagnosed the patient as having both malaria and DDS. We treated the patient with the parenteral anti-malarial agent, artemisinin. Supportive treatment and treatment of complications were also performed simultaneously for DSS. The patient experienced an oliguria episode but responded well to a diuretic. The patient was discharged after clinical and laboratory examinations showed positive progress.

Visceral leishmaniasis is the most acute form of leishmaniasis and vaccination is the best approach to control it. One of the major groups of virulence factors in Leishmania belongs to cysteine proteinase family. In this study, for the first time, the protective potential of Leishmania infantum cysteine proteinase type III (CPC) by using a prime-boost strategy is evaluated in BALB/c mice. The experiment was carried out in three groups of mice. Vaccinated group was primed with pcDNA-cpc and boosted with rCPC-DHFR in combination with CpG motif and Montanide 720 as adjuvant. Control groups received pcDNA and rDHFR or PBS. The ratio of IgG2a/IgG1, nitric oxide concentration and IFN-gamma induction in vaccinated group is significantly higher than controls. Furthermore, the parasite load of vaccinated group is significantly lower than controls. In addition, sera reactivity of visceral leishmaniasis individuals was examined and showed considerable reactivities toward rCPC in comparison with cutaneous leishmaniasis. The achieved result is highly encouraging the use of cysteine proteinases types I, II and III as vaccine candidate against visceral leishmaniasis.

Background: Diagnosis of Trypanosoma cruzi infection by direct pathogen detection is complicated by the low parasite burden in subjects persistently infected with this agent of human Chagas disease. Determination of infection status by serological analysis has also been faulty, largely due to the lack of well-characterized parasite reagents for the detection of anti-parasite antibodies., Methods: In this study, we screened more than 400 recombinant proteins of T. cruzi, including randomly selected and those known to be highly expressed in the parasite stages present in mammalian hosts, for the ability to detect anti-parasite antibodies in the sera of subjects with confirmed or suspected T. cruzi infection., Findings: A set of 16 protein groups were identified and incorporated into a multiplex bead array format which detected 100% of >100 confirmed positive sera and also documented consistent, strong and broad responses in samples undetected or discordant using conventional serologic tests. Each serum had a distinct but highly stable reaction pattern. This diagnostic panel was also useful for monitoring drug treatment efficacy in chronic Chagas disease., Conclusions: These results substantially extend the variety and quality of diagnostic targets for Chagas disease and offer a useful tool for determining treatment success or failure.

The two main agents of human malaria, Plasmodium vivax and Plasmodium falciparum, can induce severe anemia and provoke strong, complex immune reactions. Which dynamical behaviors of host immune and erythropoietic responses would foster control of infection, and which would lead to runaway parasitemia and/or severe anemia? To answer these questions, we developed differential equation models of interacting parasite and red blood cell (RBC) populations modulated by host immune and erythropoietic responses. The model immune responses incorporate both a rapidly responding innate component and a slower-responding, long-term antibody component, with several parasite developmental stages considered as targets for each type of immune response. We found that simulated infections with the highest parasitemia tended to be those with ineffective innate immunity even if antibodies were present. We also compared infections with dyserythropoiesis (reduced RBC production during infection) to those with compensatory erythropoiesis (boosted RBC production) or a fixed basal RBC production rate. Dyserythropoiesis tended to reduce parasitemia slightly but at a cost to the host of aggravating anemia. On the other hand, compensatory erythropoiesis tended to reduce the severity of anemia but with enhanced parasitemia if the innate response was ineffective. For both parasite species, sharp transitions between the schizont and the merozoite stages of development (i.e., with standard deviation in intra-RBC development time

Trichomoniasis, caused by the protozoan parasite Trichomonas vaginalis, is a major nonviral sexually transmitted disease. Clinical spectrum varies from an asymptomatic state to mild, moderate, or severe symptoms. However, the exact factors leading to the variations in symptoms have not been well elucidated. Host's immune response to the parasite may be playing a role in varied symptomatology. The present study reports antitrichomonas IgM, IgA, IgG and its subclasses in doubling dilutions of serum and diluted vaginal washes of six T. vaginalis-infected symptomatic and four T. vaginalis-infected asymptomatic women and uninfected controls by enzyme-linked immunosorbent assay (ELISA). No significant difference was observed in serum IgG ELISA absorbance values from symptomatic compared to asymptomatic subjects (p > 0.05) while a significant difference (p < 0.05) was noted in serum IgM in all the tested dilutions and IgA up to a dilution of 400. This is the first report of the detection of specific IgG subclass response in T. vaginalis-infected female patients, and quantitative analysis of the antibody responses indicated that the production of local IgG particularly IgG1 in vaginal secretions may be playing a significant role in establishing symptomatic infection. The interesting observation of the present study is that the specific IgM was detected in 2 (33.3%) symptomatic and T. vaginalis-infected patients in > or =800 dilutions and in 1 (16.6%) up to 200 dilutions in serum, while it was not detectable in the vaginal secretions of symptomatic patients or in the serum and vaginal secretions of asymptomatic T. vaginalis-infected patients.

Falciparum malaria vaccine candidates have been developed using recombinant, replication-deficient serotype 5 and 35 adenoviruses (Ad5, Ad35) encoding the Plasmodium falciparum circumsporozoite surface protein (CSP) (Ad5.CS, Ad35.CS) (Crucell Holland BV, Leiden, The Netherlands). To evaluate the immunogenicity of these constructs, BALB/cJ mice were immunized twice with either Ad5.CS, Ad35.CS, empty Ad5-vector (eAd5), empty Ad35 vector (eAd35), or saline. Another group received the CSP-based RTS,S malaria vaccine formulated in the proprietary Adjuvant System AS01B (GlaxoSmithKline Biologicals, Rixensart, Belgium). Here we report that Ad5.CS, Ad35.CS, and RTS,S/AS01B, elicited both cellular and serologic CSP antigen-specific responses in mice. These adenoviral vectors induce strong malaria-specific immunity and warrant further evaluation.

The prevalence of antibodies to Toxoplasma gondii was determined in blood and tissue exudates recovered from the spleens of 41 wolverines (Gulo gulo) collected in Nunavut, Canada, using a modified agglutination test (MAT). Antibodies to T. gondii were found in 17 (41.5%) of the 41 wolverines with MAT titers of 1:25 in 1, 1:50 in 4, 1:100 in 5, 1:200 in 6, and 1:400 in 1. This is the first report of antibodies to T. gondii in wolverines, and the results indicate that exposure is common.

We compared three biological methods for the diagnosis of ocular toxoplasmosis (OT). Paired aqueous humor and serum samples from 34 patients with OT and from 76 patients with other ocular disorders were analyzed by three methods: immunoblotting or Western blotting (WB), the calculation of the Goldmann-Witmer coefficient (GWC), and PCR. WB and GWC each revealed the intraocular production of specific anti-Toxoplasma immunoglobulin G in 81% of samples (30 of 37). PCR detected toxoplasmic DNA in 38% of samples (13 of 34). Nine of the 13 PCR-positive patients were immunocompetent. Combining the techniques significantly improved the diagnostic sensitivity, to 92% for the GWC-WB combination, 90% for the WB-PCR combination, and 93% for the GWC-PCR combination. The combination of all three techniques improved the sensitivity to 97%.