Giardia infections in humans

A short report is given on the importance of the infections of people by Giardia lamblia with special consideration of epidemiological and immunological aspects. Results of the investigations of children from different day-care centres in large town also proved interactions with pathogenic and apathogenic bacteria. The prevalence in children with diarrhoea was up to 50% contrary to children without diarrhoea (up to 14%). Adults were infected with Giardia lamblia up to 3%. Environmental investigations of the sources of infection had negative results.     

Articular manifestations of Giardia lamblia infections

Reactive arthritis due to Giardia lamblia are rare. They are usually associated with abdominal pain and diarrhoea. Epidemiological data may help for the diagnosis which may be done by parasitologic studies of stools or microscopic examination of jejunal biopsy. Recovery is easily obtained with metronidazole.     

Giardia lamblia infections in adult mice.

An adult mouse-Giardia lamblia model was developed and used to study host-parasite interactions, including antigenic variation. The H7/1 clone of isolate GS infected mice consistently and produced infections in 14 mouse strains tested. Infection patterns were mouse strain and Giardia isolate dependent. Antigenic variation occurred in immunocompetent mice but not in mice with severe combined immunodeficiency.     

Evaluation of ciprofloxacin in the treatment ofPseudomonas aeruginosa infections

The efficacy and safety of ciprofloxacin in the treatment ofPseudomonas aeruginosa infections was evaluated in 72 patients suffering from upper urinary tract infection (19 patients), deep soft tissue infection (16), chronic osteomyelitis (12), abscess (7), chronic otitis media (6), otitis externa (3) and bronchopneumonia (9). Forty-eight patients received an oral dose of 500 mg or 750 mg b.i.d. and five patients an i.v. dose of 200 mg b.i.d., while 19 patients were given both oral and parenteral doses. The duration of therapy ranged from seven days to more than four months. The MICs of ciprofloxacin for thePseudomonas aeruginosa strains isolated were in the range < 0.06–2 mg/l; 36% of the strains were resistant to all other available antibiotics. At follow-up after a minimum of six months the clinical success rate was 75% and the infecting organism was permanently eradicated in 49% of the patients. In nine patients the organism developed resistance, particularly when the initial MIC was higher than 0.5 mg/l. No significant adverse reactions were observed. Ciprofloxacin is the first antipseudomonal antimicrobial agent which can be administered orally and therefore fulfills a need in chemotherapy.     

Giardia lamblia infections in B-cell-deficient transgenic mice.

In the present study, we infected B-cell (and antibody-)-deficient transgenic mice with the Giardia lamblia clone GS/M-83-H7. These animals were inhibited in intestinal anti-Giardia immunoglobulin A (IgA) production and could not resolve the parasite infection, and antigenic diversification within the respective parasite populations occurred in an unusually slow manner. These findings indicate an important immunological function of local IgA antibodies which promotes antigenic variation of the parasite and is involved in control of the parasite infection.     

Giardia duodenalis infections in pediatrics: our series

5000 pediatric patients presenting gastrointestinal disturbance (diarrhoea, vomiting, abdominal pain or stypsis) coming from different urban and rural area of Naples (Italy) were evaluated for possible intestinal Giardiasis at the Department of Pediatrician, University of Naples, Italy. The mean age of the patients was 6.4 years and range 0.5-15 years. Giardia duodenalis was searched in 3 different specimens of stools collected every other day, by a microscopic examination by Stoll method. The presence of Giardia duodenalis was correlated with different parameters: life-style, social environment, social level, season, geographic area and subjective symptoms. Statistical differences in the different groups of patients were evaluated by the chi square test. Giardia duodenalis was found in 237/5000 patients (4.7%) of the patients. In nine of them the protozoa was associated with E. vermicularis and in 8 with T. thichiuria e the highest monthly prevalence was observed in November an December. The most frequent symptom was diarrhoea (61.1%). According to these data the Authors can conclude that Giardiasis is a frequent gastrointestinal infection even in children living in temperate areas. This infection is frequently asymptomatic, but can lead to malabsorption and/or to malnutrition, and can be cause of orticaria.     

Mast cell-dependent control of Giardia lamblia infections in mice

Mast cells are important for protective immunity to intestinal helminth infections and as mediators of allergic disease. Their role in protozoan infections is less well described. We have therefore analyzed mast cell responses and parasite control in mice infected with the protozoan Giardia lamblia. We also measured immunoglobulin A (IgA) responses to the parasite, as IgA can have a protective role in this model. c-kit w/wv mice failed to make parasite-specific IgA, mount a mast cell response, or eliminate the infection. Anti-c-kit-treated C57BL/6 mice had normal IgA responses, lacked mast cell responses, had reduced interleukin-6 (IL-6) mRNA in the small intestine, and failed to control the infection within 10 days. IL-9-deficient mice had a significant but reduced mast cell response and still controlled the infection within 2 weeks. Interestingly, IL-6-deficient mice had enhanced mast cell responses yet failed to rapidly control the infection. However, prevention of mast cell responses in IL-6-deficient mice by anti-c-kit treatment did not lead to parasite elimination. Both IL-6- and IL-9-deficient mice had normal IgA production. IL-6-deficient mice had significant serum levels of mast cell mediators, histamine and mast cell protease 1, following infection. Together, these results show that mast cells are important for the rapid control of Giardia infections in mice. Furthermore, they show that IL-6 is not necessary for these mast cell responses. Instead, they suggest that mast cell production of IL-6 appears to be important for control of this infection.     

T-cell-dependent control of acute Giardia lamblia infections in mice

We have studied immune mechanisms responsible for control of acute Giardia lamblia and Giardia muris infections in adult mice. Association of chronic G. lamblia infection with hypogammaglobulinemia and experimental infections of mice with G. muris have led to the hypothesis that antibodies are required to control these infections. We directly tested this hypothesis by infecting B-cell-deficient mice with either G. lamblia or G. muris. Both wild-type mice and B-cell-deficient mice eliminated the vast majority of parasites between 1 and 2 weeks postinfection with G. lamblia. G. muris was also eliminated in both wild-type and B-cell-deficient mice. In contrast, T-cell-deficient and scid mice failed to control G. lamblia infections, as has been shown previously for G. muris. Treatment of wild-type or B-cell-deficient mice with antibodies to CD4 also prevented elimination of G. lamblia, confirming a role for T cells in controlling infections. By infecting mice deficient in either alphabeta- or gammadelta-T-cell receptor (TCR)-expressing T cells, we show that the alphabeta-TCR-expressing T cells are required to control parasites but that the gammadelta-TCR-expressing T cells are not. Finally, infections in mice deficient in production of gamma interferon or interleukin 4 (IL-4) and mice deficient in responding to IL-4 and IL-13 revealed that neither the Th1 nor the Th2 subset is absolutely required for protection from G. lamblia. We conclude that a T-cell-dependent mechanism is essential for controlling acute Giardia infections and that this mechanism is independent of antibody and B cells.     

Evaluation of the use of ofloxacin in the treatment of various infections

We investigated the clinical efficiency and safety of ofloxacin, a new fluoroquinolone, for the treatment of various documented bacterial infections in 26 patients (10 females, 16 males) aged 17 to 84 years. Ofloxacin monotherapy was given orally in a dose of 200 mg twice (25) or three times (1) a day. Antibiotic levels and serum bactericidal activity were measured using a microbiological method on the second and sixth days, before and 2 and 6 hours after a single dose. The infectious episode treated was enterocolitis in 7 cases (5 Shigella, 2 Salmonella), Salmonella septicemia in 9 (7 typhoid fevers and 2 Salmonella minor infections), chronic osteoarthritis in 3 (1 E. coli, 2 S. aureus + P. aeruginosa), a soft tissue infection in 3 (2 S. aureus, 1 E. coli), acute pleuropneumonia in 2 (2 Klebsiella pneumoniae), pyelonephritis with bacteremia in 1 (Klebsiella pneumoniae), and pneumococcal pneumonia with septicemia in 1. Mean duration of therapy was ten days for 23 patients (range 7 to 30 days). The three patients with osteoarthritis were treated for 35, 95 and 270 days respectively. 24 patients recovered free of sequelae or germ carriage. Treatment failed in 1 case of chronic osteitis (S. aureus + P. aeruginosa) and in 1 staphylococcal soft tissue infection. No adverse reactions were observed except a slight increase in transaminases in 3 patients. Peak and through serum ofloxacin levels were 3.70 micrograms/ml and 0.95 micrograms/ml respectively on the second day and 3.25 micrograms/ml and 0.80 microgram/ml respectively on the sixth day.(ABSTRACT TRUNCATED AT 250 WORDS)     

Evaluation of prophylactic and therapeutic effects of silymarin on mebendazole-induced hepatotoxicity in cats

The aim of this study was to determine the protective action of silymarin on mebendazole-induced hepatotoxicity in cats. Twenty five healthy cats were randomly allotted into five equal groups. Cats in group A were given mebendazole (single dose 200?mg?kg, p.o.); group B consisted of cats that received silymarin (single dose 30?mg?kg, p.o.) concurrent with mebendazole administration; groups C, D and E were treated as group B, but silymarin was administered 2, 12 and 24?h after mebendazole administration, respectively. The serum concentrations of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), lactate dehydrogenase (LDH) and total and direct bilirubin were measured before mebendazole administration and 2, 12, 24 and 72?h later as indices of liver injury. A single oral administration of mebendazole significantly elevated serum concentrations of ALT, AST, ALP, LDH (in all cases), and total and direct bilirubin in one cat in group A, after 24?h (P?<?0.05). In groups B and C, levels of serum enzyme activities and total and direct bilirubin remained within normal values, but in group D, levels of serum enzyme activity (in four cases) were higher than normal values and total and direct bilirubin remained within the normal range. In group E, levels of serum enzyme activities (in all cats) and total and direct bilirubin (in one cat) were higher than normal values. In conclusion, silymarin can protect liver tissue against oxidative stress in cats with mebendazole intoxication particularly in the first 2?h after exposure.     

The macrophages as an effector cell in Giardia lamblia infections

Direct and antibody-dependent, cell-mediated cytotoxic responses exhibited against Giardia lamblia trophozoites by peritoneal macrophages of infected animals were studied. On first exposure, the infection persisted for 30 days and peak cytotoxic responses were noticed on the 20th day post infection. In reinfected animals, peak response was on 10th day and these animals were capable of clearing the infection much faster compared with animals infected for the first time. Macrophages in Giardia infection, therefore, seem to play an important role in providing resistance to infected animals as evident from significant augmentation of their cytotoxic responses in the infected animals.     

Serum IgA antibodies in HSV asymptomatic genital infections

Cervico-vaginal swabs and serum samples from 81 women without herpes-associated clinical symptoms were examined for virus isolation and for the presence of IgA antibodies to herpes simplex virus (HSV) using the indirect fluorescent antibody technique. Nineteen of the 81 women were followed up for 2 years. Blood samples and swabs from cutaneous lesions were obtained from another group of 20 women (medical staff) with herpes labialis. By analysing the specific anti-HSV IgA antibodies, a higher geometric mean titre (GMT) was found in women with positive HSV-2 isolation (GMT = 380.03), as opposed to the GMT observed in women with negative HSV-2 (GMT = 63.43) or positive HSV-1 isolation (GMT = 55.15). Results from the longitudinal study also demonstrated that positive virus isolation always correlated with a marked rise in serum IgA antibody to HSV.     

Canine kobuvirus infections in Korean dogs

To investigate canine kobuvirus (CaKoV) infection, fecal samples (n = 59) were collected from dogs with or without diarrhea (n = 21 and 38, respectively) in the Republic of Korea (ROK) in 2012. CaKoV infection was detected in four diarrheic samples (19.0 %) and five non-diarrheic samples (13.2 %). All CaKoV-positive dogs with diarrhea were found to be infected in mixed infections with canine distemper virus and canine parvovirus or canine adenovirus. There was no significant difference in the prevalence of CaKoV in dogs with and without diarrhea. By phylogenetic analysis based on partial 3D genes and complete genome sequences, the Korean isolates were found to be closely related to each other regardless of whether they were associated with diarrhea, and to the canine kobuviruses identified in the USA and UK. This study supports the conclusion that CaKoVs from different countries are not restricted geographically and belong to a single lineage.     

Giardia and other intestinal parasites in dogs from veterinary clinics in Japan

The present study is the first report that describes the national survey of intestinal parasites in private household dogs brought to veterinary clinics in Japan. A total of 2,365 fresh feces were collected. Giardia-specific coproantigen was examined by ELISA kit (SNAP^? Giardia, IDEXX Laboratories, Inc.; Maine, USA). Other intestinal parasites were determined microscopically using the formalin–ethyl acetate sedimentation technique. According to age categories, Giardia duodenalis, Cystoisospora spp., Toxocara canis, Toxascaris leonina, and Strongyloides spp., at ≦6-months-old showed significantly (P < 0.0001, P < 0.001 or P < 0.01, respectively) higher prevalence compared to >6 months old (31.5% vs. 2.3%, 9.1% vs. 0.05%, 1.8% vs. 0.4%, 1.1% vs. 0%, and 1.1% vs. 0.05%, respectively). In clinical categories, prevalences of G. duodenalis (14.8%) and Cystoisospora spp. (4.7%) in symptomatic dogs were significantly (P < 0.05, respectively) higher than those in asymptomatic ones (7.9% and 1.6%, respectively). G. duodenalis and Cystoisospora spp. were dominant parasites in private household dogs in Japan, especially ≦6-month-old dogs.     

Short term treatment of type II hyperlipoproteinaemia with silymarin

In a seven-month open clinical study on 14 type-II hyperlipidaemic outpatients, the effects of silymarin (Legalon), an antioxidant and hepatoprotective agent, were investigated. Blood lipid, lipoprotein and apolipoprotein concentrations, as well as liver and renal function parameters were measured. After determining baseline values, patients were treated with 420 mg Legalon daily for three months. After a two-month placebo period, the treatment was repeated with Legalon for a further month. In respect to the serum lipid and lipoprotein concentrations, there were no remarkable changes except that the total cholesterol and HDL-cholesterol levels slightly decreased. At the 12th week, in all cases, the apolipoprotein levels were somewhat decreased compared to the baseline values. By the significant decrease of both apo A-I and A-II values, a decrease of the total structural protein amount of HDL, and thus a relative increase in the proportion of cholesterol in HDL fraction was suggested. There were minor changes in serum protein concentration and liver function tests, but all values remained within the normal range. All of the renal function parameters remained unchanged during both treatments and the placebo periods. An additive role of Legalon in the therapy of secondary hyperlipoproteinaemia resulting from different liver diseases is discussed.     

Comparative evaluation of enzyme-linked immunosorbent assays based on crude and recombinant leishmanial antigens for serodiagnosis of symptomatic and asymptomatic Leishmania infantum visceral infections in dogs

The diagnosis of visceral leishmaniasis remains difficult in rural areas where the disease is endemic, and serologic methods still need assessment, as they are not very sensitive for the detection of asymptomatic infectious dogs. Here we present data on the development of enzyme-linked immunosorbent assay (ELISA)-based methods for the detection of antibodies against recombinant leishmanial antigens (namely, the recombinant K26 [rK26] and rK39 antigens from Leishmania infantum and the rA2 protein from Leishmania donovani) in comparison to ELISAs employing crude soluble antigen (CSA). The assays utilized sera from known negative controls (n=25) and clinically asymptomatic (n=50) and symptomatic (n=50) dogs with confirmed L. infantum infections. Additional studies were also done using sera from animals harboring other infections (n=14) for the evaluation of cross-reactivity. Our study indicated that rK26 and rK39 used in ELISAs provided very high sensitivities for the detection of symptomatic dogs (94% and 100%, respectively), followed by CSA (88%) and rA2 (70%). Conversely, rA2 was more sensitive for asymptomatic dogs (88%) than rK39 and rK26 (both 66%) and CSA (30%). Some cross-reactivity in sera from dogs with other infections (Leishmania braziliensis and Leptospira interrogans) was identified, but the rA2 protein provided the greatest specificity (98%). Data further indicate that all three recombinant proteins must be used in parallel to detect essentially all infected dogs. Efforts should be made to develop a cheap and reliable serologic test based on epitope selection from these diagnostic markers for the sensitive detection of L. infantum-infected dogs.