[Atypical vascular tumors of the gastrointestinal tract: four uncommon cases]

AIM

A small but significant percentage of vascular tumors may develop at extracutaneous location. They are difficult to detect on the physical exam and usually they require immediate intervention. Pediatric surgeons must have acknowledge of its prognostic and therapeutic implications.

PATIENTS AND RESULTS

We report 4 of these patients. Patient 1 was a healthy newborn who presented in the second week of life, recurrent severe gastrointestinal bleeding, thrombocytopenia and anemia. Diagnosis of multifocal linfangioendoteliomatosis with thrombocytopenia was established. Patient 2 had prenatal diagnosis of ascites and presented at birth sepsis, anemia, thrombocytopenia and hypoproteinemia. Upon laparotomy hemorrhagic ascites and thickening of rectum-sigmoid wall and mesentery were found. Pathologic diagnosis was Kaposiform hemangioendothelioma and the clinical course was consistent with Kassabach-Merrit phenomenon. Patient 3 had at birth, multifocal hepatic GLUT1- hemangiomatosis with severe cardiac insufficiency and coagulopathy. She died while waiting for a liver transplantation. Patient 4 is a girl who presented in the newborn period with vomiting and hematochezia. She required several transfusions and endoscopic biopsies showed a vascular tumor that infiltrated duodenum, jejunum and mesentery. Imaging studies and histologic findings on biopsy led to the diagnostic of juvenile hemangioma GLUT-1+.

CONCLUSIONS

Vascular tumors of the digestive tract may be difficult to diagnosis and their classification is still incomplete. Pediatric surgeons must be acquainted with these varieties of tumors because they are always involved in diagnosis and therapeutic decision making.

[Morbility and mortality associated with prosthetic patch in congenital diaphragmatic hernia]

AIM

To analyze morbility, mortality and neonatal intensive care management in CDH patients who required a prosthetic patch to close the diaphragmatic defects, and to compare these results with those who were made a primary closure.

MATERIAL AND METHODS

We reviewed the clinical charts of CDH patients managed at our institution between January 1994 and December 2006, including demographic data, clinical management, treatment options, complications and mortality. Appropriate statistical tests were used to evaluate the data: mortality, need of high frequency oscillatory ventilation (HFOV), days of intubation, days of total parenteral nutrition (TPN), days of admission, reherniation, need of Nissen funduplication and intestinal obstruction; a p value less than 0.05 was considered statistically significant.

RESULTS

Eighty-seven CDH patients were reviewed, 68 right, 17 left and 2 bilateral defects. Seventeen died before surgery (19.5%). Among the 70 operated patients, 21 (24.1%) required a prosthetic patch, 18 in the left and 3 in the right side. Overall mortality, need of HFOV, intubation days, need of TPN, days of admission, reherniation rate and need of Nissen funduplication were all significantly worse in the group who required a patch. Rate of intestinal obstruction was similar in both groups.

CONCLUSIONS

Patients who required a prosthetic patch to close the diaphragmatic defect suffered from higher morbidity and presented a higher mortality than those who did not required the patch.

[Reoperations in gastroesophageal reflux disease]

PURPOSE

The purpose was to determinate the indications in which the failure of the surgical treatment of the gastroesophageal reflux disease (GERD) is more frequent and to analyze the results of the reinterventions.

PATIENTS AND METHOD

We made a restrospective review of the patients who underwent reoperation at our Institution during 1992-2006.

RESULTS

19 of 252 Nissen underwent reoperation. In one case was the fourth fundoplication, in another was the third and the second in the rest of them. The reflux was confirmed by upper gastrointestinal contrast study, endoscopy, pH monitoring and, in some cases, manometry. 5 cases have surgical comorbidity (3 Esophageal Atresia (EA), 2 Congenital diaphragmatic hernia (CDH), 4 patients was neurologically impaired, 1 had caustic stenosis (CS), and 9 only symptoms of GERD. 8.7% of the patients with GERD, 5.8% of the neurologically impaired children, 10% of the EA, 20% of the CDH and 50% of the CS underwent redo Nissen. The mean time between first and second fundoplication was 1.6 years (range = 1 m-5.5 y). It was 11.2 in neurologically impaired patients, 5 m in CS, 11.5 m in CDH, 2.4 y in EA and 2.8 y in the rest. In patients with respiratory disease, the mean was 1.1 y and 1.9 y in the rest. The mechanism of failure was herniation of the fundoplication through the hiatus in 8 cases, wrap incompetence in 4 and wrap dehiscence in 2. In 5 patients it couldn't be determined. There were 2 postoperative complications. The mean follow-up was 5.3 years (range = 6-151.5 m). There was no cases of mortality. 17 of the 19 patients (89.4%) are free of symptoms and don't need more treatments. The child with CS continuous periodic esophageal dilatations and 1 of the patients with EA has dysphagia to solid foods.

["The swallowed bullet": illustration of a rare missile trajectory in a pediatric gunshot neck injury]

BACKGROUND

The probability of a bullet deglutition is a remote cause of consultation.

OBJECTIVES

To communicate a clinical case of gunshot wound's penetrating cervical trauma in a pediatric patient, with a no frequent trajectory.

METHODS

We describe and illustrate a clinical case of penetrating neck gunshot wound in the left zone III. At the initial radiological examination, we observed an intraabdominal location of the bullet. The analysis of the clinical case demonstrated an oropharyngeal injury, and a "swallowed bullet", without other lesions.

RESULTS

We observed a satisfactory evolution with a nonsurgical management. There was no associated morbidity.

CONCLUSION

The gunshot bullet's trajectory generally implies a multiple organs lesion. In this case, the initial radiological location of the bullet deserved to rule out cervical, intrathoracic and intraabdominal organs injuries, allowing illustrate this infrequent and almost "harmless" trajectory.

[Surgical treatment in severe dog bites injures in pediatric children]

INTRODUCTION

We report a retrospective study of dog-bitten-children who underwent surgical treatment in our department between 1995 and 2005. We checked the different surgical techniques used to cover the defect as well as short and long-term functional and aesthetic results, considering also infection and hospital stay.

MATERIALS AND METHODS

During this period of time, 21 patients received surgical treatment because of dogs bites. Surgical approach was decided considering location and severity of lessions.

RESULTS

Our serie consists of 12 males and 9 females. Head (71%) and extremities (23%) were the most frequent affected areas. Primary closure was carried out in 18 cases and in the remaining 3 artificial skin or tissue flaps were needed; in these 3 cases the resulting scar was later removed. Surgical infection occurred in less than 10% of the children and in all cases, long-term aesthetic results were considered excellent.

CONCLUSIONS

Primary closure of dog-bites-injures improves functional and aesthetic results and reduces the surgical procedures in those patients.

[Pediatric patient in adult age. Long-terms results of esophageal replacement]

BACKGROUND

Esophagocoloplasty is one of the most used procedures for esophageal replacement in children. Considering high life expectancy in these patients, long-term results must be considered when evaluating this technique. The aim of our study is to evaluate quality of life of adult patients who underwent surgery at pediatric age.

PATIENTS AND METHODS

We report a retrospective study of 99 patients who underwent esophageal replacement in our institution between 1966 and 2006. Eight of them have died and 63 out of the remaining 91 are over 18 years now and represent our study serie. Long-term results and actual situation of those patients, considering psychological, physic and social aspects, were evaluated through clinical review and telephonic interview. Karnofsky index was applied to mesure functional ability from 0-100% (bad, medium, good-excellent) according to the answers the patients gave to our questions. We also recorded their health personal experience and subjective evaluation of their quality of life.

RESULTS

Sixty-three patients were reviewed (43 males and 20 females) with a mean age of 4.3 +/- 3.4 D.S. Mean follow-up time was 29.6 +/-7.7 years. Indications for esophageal replacement were as follows: caustication (n = 32), type III esophageal atresia (n = 15), type I AE (n = 13) and others (n = 3). In 48 patients the graft was placed in retroestenal position and in 15 cases retromediastic location was used. Postoperative period was uneventful in 44% of the patients, being the most frequent early complications in the remaining, cervical leakage and stenosis. Long-term, 56,8% did not have any sequelae, 28.5% required further surgery and the remaining 43.13% presented the following complications: symptomatic graft reflux (22), scoliosis and thoracic asymmetry (12), colonic redundancy or cervical diverticulum (7), food impaction (6) and failure to thrive (5). Only one 38 year old patient does not have intestinal tract continuity nowadays. Thirty-one patients have a Karnofsky index > or = 80-100%, being considered healthy and able to have a normal activity. Eighteen patients are included between 40-80%, being the most frequent limitation the need of medication to avoid reflux, backache and occasional episodes of food impact. Only 2 patients have Karnofsky index inferior to 40%. None of them are under 20%.

CONCLUSIONS

Esophagocoloplasty allows restoration of intestinal tract continuity in almost all cases and the mortality of this procedure has decreased over time. Even though some risks are still remarkable, it offers long-term good results with little repercussion on functional ability in adult age. Most of the patients consider themselves healthy and enjoy an acceptable quality of life.

[Aplasia cutis congenita: surgical treatment and results in 36 cases]

INTRODUCTION

Aplasia cutis congenita is a rare congenital absence of skin most commonly affecting the scalp. Although most defects are small and superficial, approximately 20% of cases involve absence of the skull. Such defects expose the brain and sagital sinus, with concomitant risk of fatal hemorrage, infection, or both. This anomaly most commonly presents as a solitary defect, but sometimes it may occur as multiple lesions. The lesions are noninflammatory and well demarcated, and range is variable from 0.5 cm to 10 cm or more. Although the majority of these scalp defects occurs sporadically, many family cases have been reported. Multiple causes have been suggested for aplasia cutis: genetic causes, syndromes and teratogens, intrauterine infection -varicella zoster virus, herpes simplex virus-, fetal exposure to cocaine, heroin, alcohol or antithyroid drugs.

MATERIALS AND METHODS

A retrospective study of children with Aplasia Cutis Congenita who received treatment in Hospital La Paz, in Madrid between 1995 and 2005 was undertaken. We checked location, moment of the surgery, type of surgery and aesthetic results.

RESULTS

In the 20 year period between 1985-2005, we treated 36 patients with Aplasia Cutis. 33 of them have the scalp affected and only in 3 cases the trunk was involved. In 4 cases there was an absence of the skull, two slight and two severe. 3 patients had Adams-Oliver and one Cutis Marmorata Telangiectasica syndrome. Fifteen patients were operated in neonatal period with direct closure or advancement or rotational flaps, and in 17 cases the late treatment included use of tissue expanders to cover definitely the defect. One of the patients died for bleeding of the sagital sinus while was waiting for the secondary closure of the wound, and other patient required complex skull reconstruction to achieve a complete coverage.

CONCLUSIONS

In view of our experience and results, we believe that early surgery prevents vital risks, reduces local complications and makes easier the final reconstruction.

[Early surgical treatment in nasal tip hemangiomas: 36 cases review]

BACKGROUND

Hemangiomas are the most common benign tumours in infancy. Its trophoblastic origin is now confirmed and it would explain their increasing incidence that runs parallel to the more frequent use of fertilization in vitro techniques and the high rates of prematurity and twinning. It is not a coincidence that they appear more often in the face and its location is related to the merging lines of the facial embryonal buds. Nose tip, upper-eyelid and orbital regions are special areas that need a different approach in each case. Over the last years we changed our therapy protocol for these tumours, in an attempt to decrease the psychological, social and scholar impact in children.

PATIENTS AND METHODS

During the last 20 years, 36 patients with nasal tip hemangiomas underwent surgical treatment in our institution. We divided them into two groups, those treated between 1985 and 1992 (n=l1) and those treated between 1992 and 2005 (n=25). Traditionally, conservative management including close observation, corticosteroid therapy and finally surgical treatment of the sequelae, was proposed. Late surgical treatment was reserved for incompletely regressed or unsuccessfully treated facial tumours. Our more recent approach involves early surgical excision, in order to avoid psychological distress and cosmetics defects. Age at diagnosis, appearance at that moment, sort of treatment and time of surgical procedure were recorded to evaluate long-term results.

RESULTS

In this paper we report our series of 36 patients, consisting of 26 females and 10 males, with a mean age of 5 +/- 2 months at the first visit. In 11 patients from the first period (1985-1992), corticosteroid therapy was applied waiting the spontaneous regression and they finally underwent delayed surgical treatment at a mean age of 8 years. In the remaining 25 patients treated in the second period, early surgical excision was carried out with a mean age of 3 years and before school age. Indications for corticosteroid therapy include uncontrolled growth and complications (ulceration).

CONCLUSIONS

The approach to management of nasal tip hemangiomas should be individualized and must take into account their depth, location, rate of involution and functional disturbance. Children age as well as psychological problems arising from the presence of proliferative hemangioma must be considered when deciding a surgical approach. Upon the high rates of scholar failure in children with deforming hemangiomas, the lack of response to medical therapy and the need of surgical treatment in all cases, our policy now it is to attempt surgical excision and reconstruction before school age. Based on data reported and on our own experience, we consider that very early surgical treatment improves quality of life of our patients and their families.

[Complex lymphatic malformations: diagnostic and therapeutical implications]

BACKGROUND

Complex lymphatic malformations (CLM) consist of disturbances of lymphatic system development, most often with a genetic origin and with mixed vascular system involvement: lymphatic, venous and capillary. They affect a large corporal area or are associated to other syndromes or systemic diseases.

METHODS

We reviewed 21 patients with CLM treated in our hospital during the last 15 years. We used D2-40 monoclonal antibody (by immunohistochemistry) as lymphatic marker to evaluate the level of lymphatic involvement. Furthermore we analysed surgical implications in this group of patients.

RESULTS

Twelve children had only lymphatic involvement and nine mixed lymphatic-capillary or lymphatic-venous one. Two died of: respiratory insufficiency (in the neonatal period) and refractory hypoproteinemia (at 8 years of age). The skin was affected between 10 and 35% of total body surface. Three patients suffered from visceral involvement (lungs and mediastinum) and eighteen musculoskeletal. Severe deformity (20), lymphorhagia (15), repeated lymphangitis and chronic pain (5) were the most common symptoms reported. The immunoreaction intensity with monoclonal antibody D2-40 was related to the severity of the local and systemic involvement as well as to the presence of associated malformations. Fifteen cases underwent sequential surgical treatment, seven were treated with sclerotherapy (OK-432) and four with CO2 laser vaporization. Residual lymphorhagia in patients with total extirpation of the lymphatic malformation stopped after repeated evacuator punctures and healing took place.

CONCLUSIONS

(1) D2-40 monoclonal antibody is a marker of bad prognosis in CLM. (2) The complete excision of the lymphatic malformation lead to healing and the associated lymphorragia should not be considered as a recurrence, which will stop with evacuator punctures in all cases. (3) A multidisciplinary team approach is essential for the proper care of CLM in order to minimize postoperative sequelae and late complications.

[What can we do when a esophagocoloplasty fails?]

BACKGROUND

Postoperative complications of esophageal replacement are potentially severe, and they can even make impossible the digestive continuity. However, several surgical options have been used for such situations. The aim of the study is to assess the early and late results in patients who have been managed or referred to our department for this problem.

PATIENTS AND METHODS

We reviewed 8 patients operated between 1975 and 2005, four of them were referred from other hospitals. The ranging in age was from 4 months and 23 years at the moment of the first colonic replacement, and who required a second plasty because of intra or postoperative complications. The esophagocoloplasty was retrosternal in 6 cases and transhiatal in 2, with a left colon graft in 6, ileocolonic in I and right colon in the last one. The initial diagnosis was traqueoesophageal fistula in 6 (type III in 3, type I in 2 and IV in 1), caustic injury in 1 and herpetic esophagitis in 1. Complications requiring reoperation were stricture of the cervical esophagococolic anastomosis because of postoperative dehiscence (n=4), perioperative deficient graft vascularisation (n=2), graft necrosis (n= 1) and symptomatic gastric-colic reflux (n=l).

RESULTS

The deficient graft irrigation was detected and managed during the surgical procedure in 2 cases, left colonic graft was remplaced by a gastric tube and the right colon, respectively, with excellent results. Repeated endoscopic dilatations (n=4) as well as surgical revision with resection and reanastomosis of the stenotic segment (n=2), did not suffice in children with severe strictures (100%). A second plasty was tried in 2 patients: a failed microsurgical sigmoid graft in one of them, and a presternal esophagocoloplasty with a left colonic graft in the other one. It was impossible to perform a new plasty in two chidren, because of the severe mediastinal fibrosis. One patient was referred with severe gastro-colic reflux and the cologastric anastomosis and the gastrostomy were refashioned. Another patient with graft necrosis required total resection of the coloplasty and a new esophagostomy and gastrostomy. 50% of the patients recovered digestive continuity, and nowadays three of them eat normally. The fourth one died after several years because of an Guillain Barré syndrome. Four patients are still waiting for future attempts of esophageal substitution.

CONCLUSIONS

There are surgical options to reestablish the digestive continuity whenever the initial esophageal replacement fails. Severe postoperative strictures do not dissapear with endoscopic dilatations or stenotic resection and reanastomosis, but they usually require a new graft in another less injured place. Poor vascularisation of the graft can be prevented, giving the best solution for each patient, and at minimal suspicion of ischemia, consider another plasty or access during the operation.

[Esophageal replacement. 12 years experience]

Esophageal replacement is a surgical procedure rarely indicated in children. It is used in esophageal atresia type I and long-gap atresia when anastomosis is not possible, corrosive strictures and other unusual causes. Type and location of the graft depend on etiology and surgeon preferences. We analyse our results of a large series of esophageal replacement.

METHODS

. We reviewed esophageal replacements carried out in our department between January-1992 and December-2004. We report 29 patients (15 girls and 14 boys) with ages ranging from 2 months until 14 years old (median 24 months). 11 (37.9%) had esophageal atresia type I, 7 (24.1%) long-gap esophageal atresia, 8 (27.5%) caustic esophagitis, 1 herpetic esophagitis, 1 candida esophagitis and 1 esophageal necrosis due to sclerotherapy. Colon was used for substitution in 25 cases (86.2%) and stomach in 4 (13.8%). Graft location was retromediastinal in 25 children (86.2%), retrosternal in 3 and subcutaneous in 1. Native esophagus was removed in all but 2 out of 3 retrosternal cases.

RESULTS

After a follow up between 7 and 145 months (median 76 months) all children have a functional graft. Actually all patients tolerate oral feeding in a satisfactory way, and have had a normal pondostatural growth. Post-operative complications were pyloric obstruction in 3 patients (10.3%), upper anastomosis stricture in 3 (10.3%), 2 (6.9%) surgical wound evisceration, 2 (6.9%) diaphragmatic hernia, 1 (3.4%) retro-mediastinal abscess and 1 (3.4%) colo-gastric emptying difficulties. Also 2 pleural effusions, 1 cervical wound abscess and 1 abdominal wound one. Re-operation was needed in 11 patients (38%) due to these adverse events. Other complications were conservatively solved: 6 (20.7%) salivary fistula, 1 intestinal suboclusion and a dumping syndrome. One girl died due to a mycotic mediastinal abscess with perforation of the aorta 11 days after surgery. Overall survival was 96.5%.

CONCLUSIONS

Esophageal replacement has limited indications. It allow a good functional result, with adequate oral feeding and normal growth. We believe that both colon and stomach have similar outcomes, but gastric pull-up is easier to perform. It is a major surgery whose risk of complications is higher in early post-operative time.

Granuloma anular diseminado localizado en zonas fotoexpuestas

Granuloma annulare is a benign dermatosis of unknown etiology and chronic course, with different clinical variants. The disseminated form predominantly affects the extremities, sparing the trunk. We present the case of a 52-year-old woman with recurrent and autolimited outbreaks of disseminated granuloma annulare that began at summer time and involved the legs, arms and the dorsal area of hands. No pathological findings were observed in the laboratory studies performed. Histopathological examination confirmed our clinical suspicion. The development of granuloma annulare in photoexposed areas and sun exposure as a precipitating factor have been rarely reported in the literature.

[Results of the treatment of congenital diaphagmatic hernia with conventional terapeutics modalities]

AIM

In this study, we analyze our results in the treatment of congenital diaphragmatic hernia (CDH) using conventional ventilatory therapy without ECMO.

PATIENTS AND METHODS

fifty one CDH patients (27 males and 24 females) treated at our institution between 1997 and 2004 were reviewed. Data referred to obstetrics, prenatal diagnosis, newborn care, type of hernia and surgical treatment were analyzed. We recorded ventilatory treatment modalities and the outcome of the patients. We also compared the survival of our series with those expected using the formula proposed by the CDH study group in 2001. We finally analized separately those patients with early clinical presentation and who fulfilled ECMO criteria. Data from necropsies were also recovered when available.

RESULTS

Prenatal diagnosis was made in 58% of the patients. Fifty nine percent were born by c-section. The diaphragmatic defect was left-sided in 42 patients, right in 8 and bilateral in 1. Ten patients needed a prosthetic patch to close the defect. Eighteen out of the 51 patients (35%) died, 11 of them without surgical treatment. Early presentation of clinical picture was evident in 44 patients; among them 46% required high frequency ventilation and 53% nitric oxide therapy. Medium age at operation was 56+/-49 hours. The 7 children with late clinical presentation are alive. Among the 44 remaining patients, 26 are also alive (59,09%), data similar to those expected by the formula (62.39%, p>0.05). Fifteen patients had oxigenation index (IO) over 40, with a stimated survival rate of 48%, a statistically significant lower rate when compared to patients with IO<40. None of the patients with IO>40 survived; in 4 out of the 7 available necropsy studies, a severe lung hypoplasia was found (index lung weight/body weight <0.006). Among the remaining 27 children with IO<40, 24 (90%) are alive.

CONCLUSIONS

A survival rate over 90% can be achieved by conventional ventilatory measures in patients with IO<40. In our experience, children with IO>40 are rarely candidates to ECMO therapy because of the associated severe lung hypoplasia confirmed by necropsy studies.

The transplantation donation process in the Centro de Investigaciones Medico Quirurgicas of Cuba: 1999-2002

OBJECTIVE

In 1998 in the Centro de Investigaciones Medico Quirurgicas the Transplant Coordination Office (TCO) was created, with the aim to organize a system to support a hepatic transplantation program. This organization, which changed the transplantation-donation process not only in our center but in the whole country, is described in this article.

METHOD

The files of donors generated in our hospital were studied together with the transplant coordination records, from 1999 till the first half of 2002.

RESULTS

In the period studied, 21 potential donors were diagnosed with brain death, yielding a donation rate of 71.4%. Brain death was most frequently caused by vascular brain disease; however, in the realized donor group, the cranioencephalic trauma predominated. The typical donor was a man of average age 39.2 years (range, 18-86 years). Among the potential donors, 24% were excluded based on medical criteria, and 5% due to family objections. Forty liver transplantation were performed in 36 patients including 1 liver-kidney simultaneous procedure. The principal etiologies for transplant included hepatitis C virus cirrhosis, 22%; alcoholic, 19%; and acute hepatic failure, 13%. Kidney transplantations were performed in 70 patients, including 41 from cadaveric donors (53.6%) and 29 from living related donors (41.4%). In 2001, a pancreas-kidney transplantation program was started.

CONCLUSION

The creation of the TCO has been of paramount importance to optimize transplantation program functions.

[Toxigenic Vibrio cholerae: identification of the ctxB gene]

BACKGROUND

A specific probe was designed to identify part of the genetic sequence of the ctxB gene which encodes for the B subunit of the cholera toxin by polymerase chain reaction (PCR) which amplifies a 318 bp segment of the ctxB gene. Marked with P32, we used this probe for colony hybridization which is a technique for identifying the production capacity of subunit B of strains of Vibrio cholerae O1 from different outbreaks in South America (Perú 1992 and Ecuador 1993-1995) and from, collection strains. This probe was tested for the identification of the ctxB gene in Vibrio cholerae O139.

METHOD

Thirty-eight phylogenetically related strains were studied: 24 V. cholerae O1, 4 V. cholerae non O1, 5 Aeromonas, 4 Plesiomonas and 1 Escherichia coli.

RESULTS

The probe demonstrated to be useful for the identification of the ctxB gene (which codifies for the subunit B of the cholera toxin) in 24 strains of Vibrio cholerae O1 and in the Vibrio cholerae O139 strain. The ctxB gene was not detected in the remaining strains pertaining to the Vibrio cholerae non O1 species (non O139), Plesiomonas, Aeromonas spp. and E. coli. The specificity of this product was not demonstrated since no signal of unspecific hybridization appeared with phylogenetically related strains such as Escherichia coli K88 (LT+) and Aeromonas hydrophila ATCC (LT+), producers of the thermolabile LT toxin. It is important to indicate that the ctxB gene in V. cholerae O139 has been identified, for the first time, with our probe and thus it may be said that all the strains which have genetic codification for CT up to now may be identified.

CONCLUSIONS

We conclude that the system herein described provides advantages over the immunologic and biologic methods for evaluating a large number of samples in a short time and with excellent specificity and sensitivity which are important in the diagnosis and the epidemiologic surveillance of the disease.