[Diagnostic performance of graphical anomalies in the detection of large platelets and platelet clumps]

Thrombocytopenia is a current situation for making a blood smear in routine practice in a medical analysis laboratory. Recent automated hematology analyzers enumerate platelets and generate histograms and specific flags. Operators must be aware of the characteristics of their analyzer in order to avoid spurious results in the case where microscopy review is not possible.

OBJECTIVE

We evaluated the diagnostic performance of various graphical anomalies in the detection of large platelets and platelet clumps.

PATIENTS AND METHODS

Three hundred cases of thrombocytopenia were included in the study on the basis of a platelet count less than 150 × 10(9)/L. This evaluation is expressed by the results of the sensitivity, specificity, positive predictive value and negative predictive value compared to the microscopic review of blood smear.

RESULTS

Graphical performances are variable according to microscopic review of blood smears. Indeed, a not fitted curve is the most sensitive change on platelet histogram to the presence of large platelet. A high specificity to the presence of platelet clumps is announced when the platelet curve fails to return to the baseline. Moreover, characteristic findings on the DIFF scattergram are very specific to the presence of platelet clumps.

CONCLUSION

A normal platelet histogram can validate with great confidence thrombocytopenia in cases where a blood smear cannot be read immediately.

[Evaluation of the measurement of capillary glucose concentration versus plasma glucose in the newborn]

BACKGROUND

The reliability of blood glucose monitoring in neonatology is not always confirmed. The aim of this study was to evaluate the reliability of blood glucose measurements made with three different devices in newborns.

PATIENTS AND METHODS

The study was prospective, conducted in a medical and neonatal intensive care department over a period of 4 months. Capillary glucose level was measured with three different glucometers and compared with venous glucose level determined using the hexokinase method. An ANOVA and Scheffe test were used for the correlation analysis.

RESULTS

Three hundred and nine infants were included, with a mean age of 55h and a mean term of 39 weeks of gestation. Mean blood glucose in the laboratory was 0.62±0.15g/L, 0.71±0.17g/L for Accu-Chek(®) Active, 0.80±0.17g/L for Accu-Chek(®) Performa, and 0.83±0.12g/L for Bionime. An ANOVA showed statistically significant differences between the measurements made by glucometers compared to the reference blood glucose levels, and the Scheffé method showed that glucometers overestimated the real plasma glucose levels.

CONCLUSION

None of the devices used in this study was satisfactory. However, an estimation of blood glucose taking into consideration this numerical overestimation would allow early detection of hypoglycemia.

Geographical distribution updating of Tunisian leishmaniasis foci: about the isoenzymatic analysis of 694 strains

Over a period of ten years, a series of 694 Leishmania strains from Tunisian leishmaniasis foci were isolated and identified by isoenzymatic analysis. Strains were obtained from human cutaneous and visceral leishmaniasis in immunocompetent subjects, visceral leishmaniasis in imunocompromised individuals and from dogs with visceral leishmaniasis. Two classically dermotropic species, Leishmania (L.) major and Leishmania killicki were found. L. major with the single zymodeme MON-25 was the most isolated in cutaneous leishmaniasis foci of the Centre and South of Tunisia with a recent northern extension. L. killicki zymodeme MON-8 was sporadically found both in its classical microfocus of Tataouine in southeastern Tunisia as well as in some new foci in Southwestern, Central and Northern Tunisia. Leishmania infantum with its three zymodemes MON-1, MON-24 and MON-80 was isolated from both visceral and cutaneous human cases. The majority of L. infantum strains were found in the Northern part of the country; however, some strains were reported for the first time in the Southern part. L. infantum MON-1 was the only zymodeme isolated from canine leishmaniasis.

[Visceral leishmaniasis in immunocompetent adults. About six cases]

OBJECTIVE

Studying the epidemiological variations of visceral leishmaniasis in Tunisia and proving the importance of parasitological investigations to raise the diagnosis.

PATIENTS AND METHODS

Six patients hospitalised during the period between January 1998 and January 2009 at Fattouma Bourguiba Teaching Hospital in Monastir, five men and an only one woman, aged from 26 to 70 years old, originating from the central and eastern regions of the country. Epidemiological, clinical, biological and therapeutic data were obtained from the patient's medical files.

RESULTS

The major clinical symptoms were fever, weakness and spleen enlargement. Biological data revealed the presence of anaemia in every case and leucopoenia associated or not associated with thrombopenia in four cases. The diagnosis of visceral leishmaniasis was confirmed by the identification of the parasite in the blood or in the bone marrow. All patients were treated with two courses of antimoniate of meglumine separated by a 6-week interval. The outcome was positive and the patients were cured.

CONCLUSION

Visceral leishmaniasis is increasing among adults in Tunisia. Moreover, it is spreading outside its epidemiological area in the north to reach the central and southern regions. It should be raised when fever and spleen enlargement occur. Biological data are hardly specific. Diagnosis is based on finding the parasite in human fluids, mainly by molecular techniques. The rapid establishment of a specific treatment is vital.

[Evaluation of the immunoblotting for the detection of immunoglobulin G Toxoplasma antibodies in immunocompetent patients]

The serological tests commonly used for the diagnosis of toxoplasmosis raise the problem of the interpretation of the borderline immunoglobulin G (IgG) levels and discordant results between various tests.

OBJECTIVE

The purpose of our study was to evaluate the contribution of the immunoblotting in the detection of specific IgG in acquired toxoplasmosis of immunocompetent patients especially when levels are equivocal or discordant in enzyme-linked immunosorbent assay (Elisa) and indirect fluorescent antigen test (IFAT).

MATERIAL AND METHODS

[corrected] We tested three groups of sera. The first included 87 positive sera, the second 33 negative sera, and the last one 29 equivocal sera.

RESULTS

Results obtained with the first and the second group of sera led us to identify the bands 30kDa and 32kDa as markers of the toxoplasmic infection. The simultaneous presence of both bands showed a sensitivity of 91.5%, a specificity of 96.9%, a VPP of 98.7%, a VPN of 74.4% and a Youden's index of 0.88. Our findings suggest that the presence of these two bands is a reliable criterion for the confirmation of the presence of anti-toxoplasmic IgG in the corresponding serum. The immunoblot allowed us to ascertain serological status of 27 (93.1%) patients from the third group in which results were discrepant or equivocal in Elisa and/or in IFAT.

CONCLUSION

Immunoblot is a useful serological test for detection of very low or equivocal titers.

Use of PCR, IFAT and in vitro culture in the detection of Leishmania infantum infection in dogs and evaluation of the prevalence of canine leishmaniasis in a low endemic area in Tunisia

The aim of this study was to assess the use of parasitological, serological and molecular methods for the detection of Leishmania infection in blood of 67 dogs and to investigate the prevalence of canine leishmaniasis (CanL) in Kairouan (central Tunisia), an area known to be of reduced endemicity and has not been studied since 1973. Veterinarians clinically examined all dogs, and the titer of anti-Leishmania antibodies was determined by indirect immune-fluorescence antibody test. The presence of Leishmania was performed by PCR and in vitro culture. IFAT was positive in 12% of dogs and promastigote form of the parasite was isolated by in vitro culture from only 4.5% of them. However, DNA of Leishmania was detected by PCR in 20.9% of dogs. PCR was more sensitive than IFAT (p = 0.004) and in vitro culture (p < 10(-5)). A prevalence of 21% was found in Kairouan, which is significant high (p < 10(-3)) when compared to that of thirty years ago. This state is in correlation with the increase in other Mediterranean countries. Furthermore, 50% of positive dogs were asymptomatic. Preventive measures must be taken against these dogs as for symptomatic ones since their role in the transmission of the infection to vectors has been proven.

The phlebotomine fauna (Diptera: Psychodidae) of the eastern coast of Tunisia

To identify the phlebotomine sand fly populations of the eastern coast of Tunisia, an entomological survey was carried out between September and October 2005 at 71 sites located in three districts. CDC light traps and sticky papers were used to collect a total of 2,138 phlebotomine sand flies representing nine species. The predominant species occurring on the eastern coast of Tunisia are, in order of abundance, Phlebotomus longicuspis Nitzulescu, 1930 (40%); Phlebotomus papatasi Scopoli, 1786 (21%); Sergentomyia minuta Parroti Adler & Theodor, 1927 (19%); Phlebotomus perniciosus Newstead, 1911 (9.5%); Phlebotomus chabaudi Croset, Abonnenc & Rioux, 1970 (9%); Sergentomyia fallax Parrot, 1921 (1.5%); Sergentomyia dreyfussi Parrot, 1933 (0.23%); Phlebotomus langeroni Nitzulescu, 1930 (0.05%); and Phlebotomus perfiliewi Parrot, 1930 (0.05%). Species involved in the transmission of Leishmania, namely P. papatasi and P. perniciosus, represent 31% of the total number of flies captured. In the central sites (district of Monastir), P. longicuspis predominates, P. perniciosus predominates in the northern sites (district of Sousse) and P. papatasi in the southern sites (district of Mahdia), which is consistent with the distribution of Leishmania infantum and L. major in this region. Analysis of the degree of presence (D) revealed that Phlebotomus papatasi was the most common species and showed the broadest distribution (D = 95%), followed by P. longicuspis and S. minuta parroti (D = 90%) and P. perniciosus and P. chabaudi (D = 86% and 68% respectively).

[Epidemiology of Leishmania (L.) infantum, L. major and L. killicki in Tunisia: results and analysis of the identification of 226 human and canine isolates]

The epidemiological situation of leishmaniasis in Tunisia is characterised by the co-existence in a very limited territory (165,000 km2, Sahara included), of 4 clinical forms: the infantile visceral leishmaniasis (VL) and 3 cutaneous leishmaniasis (CL) forms (sporadic, zoonotic and chronic). In addition to the useful epidemiological data, identification of the causative parasitic species is essential to determine the geographic distribution of each form and to select appropriate therapeutic procedure and suitable control measures. 226 Leishmania isolates, 135 human's coming from 59 VL cases and 76 CL cases and 91 canine's were identified by the isoenzyme electrophoresis reference technique. Results confirm the endemicity of the 4 forms mentioned above. The sporadic CL, confined to the North of the country is principally caused by L. infantum MON-24 (72.2%). VL which has reached the southern ridge in the central area of Tunisia, in the governorate of Kairouan (36 typed isolates), presents an unusual high proportion of L. infantum MON-24. In fact, this zymodeme, rather dermotropic is responsible for 47.2% of the cases vs 13% in the other regions of the country where L. infantum MON-1 remains predominant with 78.3% of typed isolates, the difference being statistically significant (P < 0.01). A third zymodeme, L. infantum MON-80 is sporadically pointed out during VL or in sporadic CL. Despite the high number of canine isolates (n=91) coming from 6 governorates, only the zymodeme L. infantum MON-1 was identified, letting hypothetic the reservoir of the 2 other zymodemes of the species identified in humans. Those absences may be related to cross infections, with a low sensitivity to L. infantum MON-24 leading to a selection of MON-1 at the time of culture passages. Hence it is important to develop molecular tools of direct identification on initial biological samples without going through cultures. Zoonotic CL remains the predominant cutaneous form in the central and southern area of Tunisia. However L. killicki, agent of the chronic CL, is confirming its presence out of its original focus of Tataouine in the southern-east of the country in both zoonotic CL and VL areas.

Pediatric visceral leishmaniasis diagnosis in Tunisia: comparative study between optimised PCR assays and parasitological methods

There has been a steady increase of visceral leishmaniasis during the past 20 years in Tunisia. In this study, we assess the value of two optimised PCR versus those of classical methods for the diagnosis of human visceral leishmaniasis. 106 samples were collected from 53 cases of pediatric visceral leishmaniasis. Peripheral blood and bone marrow samples were analysed both by parasitological methods (direct examination, leukocytoconcentration (LCC) and culture) and by PCR methods with two primer pair (R221/R332 and Lei 70L/Lei 70R). We diagnosed visceral leishmaniasis in all patients: 44 cases were diagnosed by culture (83%), 42 by direct examination of bone marrow (79%), 17 by LCC (32%), and 53 positive cases with both PCR assays (R221/R332 and/or Lei 70L/Lei 70R) (100 %). Regarding each PCR assay, for blood samples, the difference between the sensitivities of PCR Lei 70L/Lei 70R (86,8%) and PCR R221/R332 (17 %) is statistically significant with p-value 0.025. For bone marrow, the sensitivities of the two PCR methods were respectively 96,2% (Lei 70L/Lei 70R) and 75,5% (R221/R332). On the whole, PCR Lei 70L/Lei 70R was more effective than PCR R221/R332 and conventional methods for the two biological samples. Moreover, the requirement of less invasive sample using blood has the advantage of being repeatable for screening and for post therapeutic monitoring.

[Cutaneous leishmaniasis caused by Leishmania infantum MON-24 in Tunisia: extension of the focus to the center of the country]

Three clinico-epidemiological forms of cutaneous leishmaniasis (CL) were described in Tunisia: the zoonotic CL (ZCL) epidemic which occurred in the centre of the country caused by Leishmania major MON-25, the chronic CL (CCL) In the south-east of the country caused by Leishmania killicki MON-8 and the sporadic CL In the North (SCL) caused by Leishmania infantum MON-24. The latter form, described in 1991, prevails in northern Tunisia with approximately thirty cases per year. Its vector, unknown for a long time could be according to the last publications, Phlebotomus perfiliewi or Phlebotomus langeroni; however, its reservoir remains unknown until now. The systematic isoenzymatic characterization permits to identify a great number of strains improving then knowledge on the eco-epidemiology of the disease. Indeed, changes were noted in the geographical distribution of these clinical forms: extension of the ZCL to the North and South, extension of the CCL to North and the SCL to the centre. We report in this note the first mention of L. infantum MON-24 in the two provinces of the centre of Tunisia: Kairouan and Sidi Bouzid, confirming the extension of the SCL to the Centre.

Post-surgical follow-up (by ELISA and immunoblotting) of cured versus non-cured cystic echinococcosis in young patients

The study was designed to determine comparatively the prognostic value of immunoblotting and ELISA in the serological follow-up of young cystic echinococcosis (CE) patients exhibiting either a cured or a progredient (non-cured) course of disease after treatment. A total of 54 patients (mean age 9 years, range from 3 to 15 years) with surgically, radiologically and/or histologically proven CE were studied for a period up to 60 months after surgery. Additionally, some of the patients underwent chemotherapy. Based on the clinical course and outcome, as well as on imaging findings, patients were clustered into 2 groups of either cured (CCE), or non-cured (NCCE) CE patients. ELISA showed a high rate of seropositivity 4 to 5 years post-surgery for both CCE (57.1%) and NCCE (100%) patients, the difference found between the two groups was statistically not significant. Immunoblotting based upon recognition of AgB subcomponents (8 and 16 kDa bands) showed a decrease of respective antibody reactivities after 4 years post-surgery. Only sera from 14.3% of CCE patients recognized the subcomponents of AgB after 4 years, while none (0%) of these sera was still reactive at 5 years post-surgery. At variance, immunoblotting remained positive for AgB subcomponents in 100% of the NCCE cases as tested between 4 and 5 years after surgical treatment. Immunoblotting therefore proved to be a useful approach for monitoring post-surgical follow-ups of human CCE and NCCE in young patients when based upon the recognition of AgB subcomponents.

[Cystic echinococcosis in children in Tunisia: fertility and case distribution of hydatid cysts]

Cystic echinococcosis, which commonly starts during childhood or adolescence, is a serious problem of public health in Tunisia. For 121 children (161 cysts), the localization and fertility of cysts as well as viability of their protoscoleces were determined. Results indicated that the lung was the primary localization of cyst (59%) followed by the liver (35%). Children's infection is more frequent in male than in female (sex ratio 1.96) and the greatest number of cases is observed in the 4-9 year age groups (94 cases). The fertility of the cyst was independent of its site or its size and no incidence of age of children was detected. Nevertheless, the fertility rate is higher in females than in males for the liver localization.

Genetic differences between Tunisian camel and sheep strains of the cestodeEchinococcus granulosusrevealed by SSCP

Ovine and dromedary Echinococcus granulosus isolates from Tunisia were identified as G1 and G6 strains based on polymorphism of the mitochondrial cytochrome C oxydase CO1. Single strand conformation polymorphism (SSCP) was used in order to examine the genetic variation within and between Tunisian G1 and G6 strains and to estimate the extent of selfing. The dromedary isolates are genetically distinct from sheep isolates (high value of genetic variation between populations: Fst= 0.46). No significant deficiency in heterozygotes was found in sheep isolates, whereas heterozygote deficiency (suggesting selfing) was found in a limited number of camel isolates.

[Faunistic note on Culcoides (Diptera, Ceratopogonidae) from the governate of Monastir (Tunisia)]

Following the arrival of blue-tongue in Tunisia, the authors report the results of the first survey made in Monastir. They show the existence of nine species of Culicoides, three of which are new to the country IC. paolae, C. imicola, C. newsteadi), that now brings to 22 the number of the known species.

Usefulness of PCR in the diagnosis of cutaneous leishmaniasis in Tunisia

We assessed the efficiency of a PCR method in establishing the diagnosis of cutaneous leishmaniasis (CL) in Tunisian patients. Four hundred and thirty specimens collected passively from patients with cutaneous ulcers suggestive of leishmaniasis attending health centres for diagnosis were included in the study. Dermal scrapings were analysed both by parasitological (examination of Giemsa-stained smears and in vitro cultivation) methods and by a genus-specific PCR detecting a fragment of the 18S rRNA gene. Microscopy revealed amastigotes in 245 samples (57.0%) and in vitro cultivation gave positive results in 88 cases (20.5%), whereas PCR detected Leishmania in 301 samples (70%). The sensitivities inferred from our results were 99.3%, 80.8% and 29% for PCR, microscopic examination and in vitro cultivation, respectively. The different forms of CL in this country are caused by three species of Leishmania and are treated with the same protocol. Of 303 well-documented cases in our study, 99% were probably caused by Leishmania major and 1% by Leishmania infantum. The lack of species-specific diagnosis is not known to affect treatment or prognosis in Tunisia. These data support the incorporation of PCR into diagnostic strategies for CL, particularly in Tunisia.

Molecular evidence of ovine (G1) and camel (G6) strains of Echinococcus granulosus in Tunisia and putative role of cattle in human contamination

Three hundred and seventy-two cysts coming from 50 humans, 166 cattle, 153 sheep and 3 camels were collected in order to establish some epidemiological molecular information in Tunisia for the first time. The analysis by PCR-RFLP of ITS1 sequence showed that all the human, ovine and bovine cysts were due to the common sheep strain of Echinococcus granulosus. The sequencing of the CO1 gene of 37 isolates confirm the G1 genotype of this strain. For seven of these isolates, we found the mutation C56T which is present in the three principal intermediate hosts: human (three cysts), cattle (three cysts) and sheep (one cyst). With regard to the G1 genotype, we identified three other point mutations. The camel strain G6 is uniquely found in the three camels isolates and not in the other intermediate hosts analysed. The fertility of the bovine cyst represents 48% that means that this host is involved in a bovine-dog cycle and consequently represents a reservoir of sheep strain in Tunisia. Our results confirm the importance of the prophylaxis measures in order to disrupt the cycle of transmission sheep-dog in Tunisia. Nevertheless, the supervision of bovine infection should be reinforced because this intermediate host may constitute an important link with the human contamination.

Anthroponotic cutaneous leishmaniasis in Tunisia: Presence of Leishmania killicki outside its original focus of Tataouine

The first three documented cases of anthroponotic cutaneous leishmaniasis due to Leishmania killicki are reported from locations outside the original focus of Tataouine in southeast Tunisia. Three strains were isolated from three patients from Gafsa, Sidi Bouzid and Seliana indicating an extension of this parasite's range towards the centre and the north of Tunisia.

Genetic relationships between sheep, cattle and human Echinococcus infection in Tunisia

Allozyme variation at seven polymorphic loci (GPI, EST, MDH, MPI, DIA, PEP, PGM) was studied to examine genetic variation within and between sheep, cattle and human populations of Echinococcus granulosus in Tunisia. A high degree of genetic similarity was shown between the cysts of the three host origins. Nevertheless, whereas, the ovine and human samples were highly similar, the cattle samples were slightly different genetically. We conclude that humans are mostly infected by parasites originating from sheep liver. The intense deficiency in heterozygotes was partly artefactual (Wahlund effect) and partly due to self-fertilisation.

Visceral leishmaniasis in Tunisia: result of the isoenzymatic characterization of 65 Leishmania infantum strains

The isoenzymatic characterization of 65 Tunisian strains of Leishmania, isolated from human cases of visceral leishmaniasis between June 1998 and August 2001, revealed the existence of 3 zymodemes of the L. infantum complex: MON-1 the most common (93.8%), followed by MON-24 (3.1%) and MON-80 (3.1%). 72% of the strains were obtained from children under the age of 5 years. The majority of the studied strains originated from 8 provinces of northern Tunisia, particularly the province of Zaghouan.

[Visceral leishmaniasis in immunocompetent children: diagnostic and epidemiologic value of peripheral leishmania blood culture]

Utilisation of new diagnosis means and particularly non invasive oues in visceral leishmaniasis can be very valuable for the biologist, the clinician as well as the patient. In this, detection of leishmania in peripheral blood, well know for VIH patients, has been applied to 37 immunocompetent tunisan children suffering from kala azar that has been shown through direct examination of bone marrow. Observed results show that culture on NNN peripheral blood medium was positive in 25 cases (67.57%). On the other side, detection of leishmania through concomitant culture of blood and marrow bone for 24 children with visceral leishmaniasis match the results in 75% of the cases. Detection of leishmania by mean of blood culture for immunocompetent children is a diagnosis mean of visceral leishmaniasis and has also an epidemiologic utility by isoenzymatic characterization of isolated leishmania strains.

[Epidemiological and clinical profile of superficial mycoses in the Monastir region (Tunisia). Retrospective study (1991-1994) of 3578 cases]

Despite of socio-economical improvement in our population and the efficacy of available antifungal treatment, superficial mycoses remain a common condition in dermatologic practice. To determine the epidemio-clinical pattern of superficial mycoses in our region, a retrospective study of 3578 cases have been carried out in the Department of Dermatology of the University Hospital of Monastir during a 4 year-period. The mean age of patients was 33 years (range: 6 months-91 years). The male to female sex-ratio was 0.82. Rural origin, history of previous mycoses, diabetes, topic or systemic corticosteroids and the presence of animals in surroundings were the most predisposing factors. The most frequent clinical patterns were: tinea corcoris and pedis (40.3%), Tinea versicolor (21.6%), Tinea capitis (9.7%) dermatophytosis of hairless skin (9.6%) and onychomycosis (8.6%). Dermatophyte was the most frequent (55.5%). The occurrence of superficial mycose especially if it affects diffuse area of the body, or if it is relapsing and resistant to treatment, requires looking for predisposing factors.

Diagnosis of human hydatidosis: comparison between imagery and six serologic techniques

Echography and/or chest radiograph in association with six serologic (immunologic) methods were tested for their ability to diagnose human hydatidosis. The immunologic techniques used were latex agglutination, counter immunoelectrophoresis, enzyme-linked immunosorbent assay (ELISA) with whole hydatid fluid and with antigen 5, a thermobabile lipoprotein that elicits the arc 5 precipitin line in immunoelectrophoresis. In this report, the results of examinations of 273 patients are presented. Of these, 243 cases were surgically proven to have hydatidosis, whereas 30 of the 273 that were strongly suspected of having hydatid cysts by radiology were shown to have other pathologies. The ELISA was more sensitive than the other methods, with 204 of 243 sera shown to be positive. The remaining 39 sera that gave false-negative results were tested using two recently developed methods, enzyme-linked immunoelectrodiffusion assay (ELIEDA) and immunoblotting (electrophoretic migration of hydatid fluid antigens under denaturing but nonreducing conditions, blotting, and immunoenzymatic assay). Immunoblotting, using our experimental conditions, had a greater sensitivity than the ELIEDA with this technique. Four of 37 sera showed one to three bands of 65, 12, and 8 kD. The sensitivity of the ELISA did not increase with either the size or type of cyst. Comparison of radiology with serology confirmed a good correlation between the two methods. Nevertheless, serology is more specific but less sensitive than imagery.