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Biomedical subjects

P P Simarro

Publications and source records attributed to P P Simarro.

At least 19 recordsLinked to original sources
PubMed2006

The elimination of Trypanosoma brucei gambiense sleeping sickness in the focus of Luba, Bioko Island, Equatorial Guinea.

After the resurgence of sleeping sickness in Luba, Equatorial Guinea, a major campaign to control the disease was established in 1985. The campaign comprised no vector control, but intensive active and passive surveillance using serology for screening, and treatment of all parasitological and suspected serological cases. Total prevalence was used to classify villages as endemic, at risk, anecdotal and non-endemic which also allowed defining the geographic extent of the focus. Active case-finding was implemented from 1985 to 2004. The frequency of surveys was based on parasitological prevalence: twice a year during intensified control, once a year during ordinary control and once every 2 years during the control consolidation phase, when the parasitological prevalence in the whole focus fell to 0.1%. From 1985 to 1999, the indirect immunofluorescent antibody test (IFAT) was used as an initial screening tool, followed by parasitological confirmation of IFAT positive cases, and the Card Agglutination Trypanosomiasis Test (CATT) if necessary. In 2000, the IFAT was replaced by the CATT. Serum-positive individuals without parasitological confirmation were subsequently tested on serial dilution. All cases underwent lumbar puncture to determine the stage of the disease. First-stage cases were treated with pentamidine and second-stage cases with melarsoprol. A few relapses and very advanced cases were treated with eflornithine. The last sleeping sickness case was identified and treated in 1995.

Agglutination Tests↗
PubMed2004

Molecular epidemiology of tuberculosis in the Bata and Malabo districts of Equatorial Guinea.

SETTING: Bata and Malabo districts, Equatorial Guinea, 1 March 1999 to 28 February 2001. OBJECTIVE: To study the molecular epidemiology of tuberculosis (TB). RESULTS: During the study period, 429 patients were diagnosed with TB in the Bata and Malabo districts. A positive culture was obtained in 206 (48%) TB patients, with RFLP analysis being performed in 185 (89.8%). Ninety-two different patterns were identified. Single patterns were found in 71 strains (38.3%) and the remaining 114 strains (61.6%) were classified into 21 clusters (of 2 to 25 patients). In addition, 37 of the typing strains were resistant to one or more anti-tuberculosis drugs, and 30 were included in clusters (81%), with 21 low level isoniazid (MIC < or = 1 microg/ml) resistance strains in the same cluster. Statistical analysis showed that resistance to anti-tuberculosis drugs (OR 3.1; 95% CI 1.2-7.6; P = 0.014), and positive smear results (4+ grade smear) (OR 4.3; 95% CI 1.5-12; P = 0.005), were significantly more frequent among patients with clustered strains. No epidemiological links were related to clustering. CONCLUSIONS: The level of clustering (61.6%) observed suggests a high degree of recent transmission and a predominance of determined patterns of Mycobacterium tuberculosis strains among the population of Equatorial Guinea.

Adult↗
PubMed2003

[The concept of neglected disease].

"Neglected disease", "neglected population" and more generally "public health negligence" are emerging concepts being put forward by numerous humanitarian groups. Sleeping sickness provides a typical example to illustrate these concepts. After causing a major epidemic in the 1930s, sleeping sickness had been practically eradicated by the end of decolonization. Because of more urgent priorities, independent national governments relinquished control activities thus allowing the disease to return insidiously. By the beginning of the 1990s the situation was comparable to that prevailing in 1930 without inciting a response commensurate with the extent of the problem. Sleeping sickness is currently not a priority and, more simply, is not given proper attention because it affects only a few people living in regions presenting little economic interest. This point underlines the especially devastating combination of neglected disease and neglected population. As early as 1999 the World Health Organization with the determined support of Medecins Sans Frontieres launched a campaign not only to promote control measures for sleeping sickness at the international level but also to use initiatives in the domain to illustrate the enormous potential for progress against neglected disease. The effects of this campaign are now beginning to be felt.

Africa↗
PubMed2003

[Status of sleeping sickness in 2003].

On May 3, 2001, the World Health Organization signed a major agreement with the pharmaceutical industry for the supply of drugs necessary for treatment of sleeping sickness. At that time Dr. Gro Harlem Brutland, director of the WHO, announced, "We can now look forward to halting the spread of sleeping sickness...". The purpose of this article is to take a look at the situation two years later. A first assessment showed that most national programs for the control of human African trypanosomiasis (NPCHAT) had practically become inoperative. One of the first steps in the new eradication campaign consisted of reviving these NPCHAT teams. However this goal could be achieved only insofar as awareness of the severity of the disease and of the need to act was felt at every level of decision-making. In 2001 the Pan-African Tse-Tse Trypanosomiasis Eradication Campaign (PATTEC) initiative was launched by African State leaders to promote special attention at the ministerial level, high-level training, and international cooperation sometimes involving several NPCHAT teams. Actions in the field include trials using new strategies, expert assistance for personnel throughout the duration of prospection, and screening and immediate treatment of numerous patients in outbreak areas where the disease was thought to be extinct. Although progress has not always been measurable in concrete terms, the dynamics have shifted almost everywhere.

Africa↗
PubMed2003

[Sleeping sickness, forgotten illness: what are the consequences in the field?].

For nearly 25 years, sleeping sickness was forgotten and increasingly neglected. Research programs and control activities against human African trypanosomiasis were discontinued. Statistical studies show a constant decrease in the number of people screened and cases detected and little change in the ratios of actively versus passively diagnosed cases and of the early (blood and lymph involvement) versus late (cerebral involvement) stage cases. In the field neglect of the disease led to deterioration not only physical facilities but also human resources. As teams aged, senior members were often replaced by less than fully qualified people resulting in a decline in efficiency and organization. Many basic notions were lost and the albeit scarce innovations in diagnosis and therapy were often overlooked. When the fight against sleeping sickness was finally resumed, these factors had to be taken into account. Efforts in the field have been focused on four areas: renovation of equipment, didactic and practical training for health care personnel, development of a decision-making algorithm based on diagnostic findings, and implementation of new therapeutic protocols.

Algorithms↗
PubMed2003

[Human African trypanosomiasis in an urban area: an emerging problem?].

The human African trypanosomiasis is essentially a rural disease. The notification of cases in urban area has always been incidental; either a diagnosis made in town revealed a disease contracted in rural environment or it meant the preservation of a complete epidemiological cycle in a remaining urban micro-focus. In Kinshasa, in Democratic Republic of Congo, about forty cases have been notified each year. All of them came from the nearby foci of Bandundu, Lower Congo and Kasaï. In 1996 the number of cases reached suddenly 254 and today the average annual number comes up to 500 in spite of all the efforts undertaken to fight the disease. A study of cases in 1998 and 1999 shows that patients are essentially distributed in suburbs and that the most affected by the disease are the 15-49 year old ones whose job is related with agricultural or fishing activities. Two phenomena seem to explain this sudden increase: the massive inflow of refugees in outskirts of town coming from provinces where trypanosomiasis is endemic and a major economic crisis throwing out urban population in suburbs living on a subsistence micro-agriculture. These concomitant factors have contributed to the setting up of a trypanosomiasis belt around the capital. Today a strategy has to be reconsidered in order to fight against the disease in the capital itself and to make the medical staff aware of the diagnosis of a disease still unknown in their sanitary district.

Adolescent↗
PubMed2002

[Sleeping sickness: one hundred years of control strategy evolution].

Sleeping sickness has been known since the fifteenth century but the real progress in the knowledge of the disease occurred in the nineteenth century with the development of microscopy. From 1841 to 1901 the parasites and their vectors have been identified, the symptomatology and the epidemiology have been described. However, due to absence of any effective cure, the campaign against the disease was still based on the isolation of the patients and the transfer of exposed populations. The discovery of atoxyl in 1905 provided doctors with their first therapeutic weapon and, in 1910, the first action of vector control was undertaken with success in the Island of Principe. Between the two world conflicts, Jamot published the rules to fight against major outbreaks. Their application in Oubangui-Chari, in Cameroon and in French Occidental Africa brought tremendous results and signed the triumph of the mobile unit concept. Success which will not be denied until the sixties when the disease was believed to be eradicated. From the sixties to the nineties, the concept of the integration of prevention and care added to the exclusion of any vertical system will result in a progressive reniewed outbreak of the sleeping sickness in the known foci. As a paradox, it is a time rich in discovery as regards diagnosis, treatment and entomology. In 1994, the World Health Organisation got concerned with the situation of the disease in Central Africa where the outbreak of the disease reinforced. A second paradox appeared; it is the next to total disinterest from the politics and fund raisers which will save the disease. Today, sleeping sickness is the typical example of the orphan disease, a show case brandished by all the good souls. In 2001, an agreement between the WHO and the pharmaceutical industry brings back the financial funds required to fight the disease. Basically, it is a matter of resuming the action by using what is still existing and by creating new strategies considering the extreme lack of human and logistical resources. The objective is to eradicate the sleeping sickness as a public health problem. The challenge is huge, but is on the way to success.

Africa↗
PubMed2001

Increased trypanolytic activity in sera of sleeping sickness patients after chemotherapy.

We tested sera from patients previously treated for human African trypanosomiasis, from patients infected with trypanosomes, and from individuals never diagnosed with African trypanosomiasis living in the Trypanosoma brucei gambiense sleeping sickness focus of Mbini in Equatorial Guinea for their trypanolytic activity against bloodstream forms of T. b. rhodesiense expressing a metacyclic and bloodstream variant surface glycoprotein (VSG). Nearly 80% of the sera from treated patients showed high trypanolytic activity against trypanosomes expressing a metacyclic VSG. The trypanolytic activity of part of these sera was mediated by IgM while that of the other part was antibody-independent. On the other hand, only 40% of the sera exhibited high trypanolytic activity against trypanosomes expressing a bloodstream VSG which also was almost completely abolished by heat-inactivation. In contrast, most sera from infected and negative individuals displayed only low to moderate trypanolytic activity against either trypanosomes expressing a metacyclic or a bloodstream VSG. These results suggest that trypanolytic activity of sera increases after African sleeping sickness and is directed against trypanosomes expressing metacyclic VSG.

Animals↗
PubMed2001

[Cost of a national program to control human African trypanosomiasis in the high Mbomou region, Central African Republic].

An outbreak of human African trypanosiaisis is ongoing in the High Mbomou area of the Central African Republic. This area is located on the Sudanese border approximately 1,100 kilometers from the capital city of Bangui. According to current estimates, the cost of implementing the National Human African Trypanosomiasis Program is 754,000 United States Dollars, i.e., 4.1 dollars per protected inhabitant. However actual conditions in the field suggest that this estimate should be revised. Special field conditions include constant refugee movement across the border, lack of accurate epidemiological data concerning neighboring Haut Zaire, and low participation of village residents in mass screening operations (less than 50%). In response to these problems, the authors recommend the organization of more exploratory missions to allow better targeting of screening and therapy. In the initial plan, exploratory missions were to account for 1% of the total cost. This proportion will probably require upward adjustment.

Central African Republic↗
PubMed2001

[Control of human African trypanosomiasis: back to square one].

The natural history of sleeping sickness is cyclic. The first epidemic outbreak in the 19th century devastated the population and resolved spontaneously for lack of victims. Intensive development during the colonial period and the movement of population that it spawned led to another epidemic in the early 1920s that reached such severe proportions that drastic steps had to be taken. At that time, Jamot was given complete political, administrative, and financial freedom to combat the disease. This program led to the development of the mobile team concept and so-called vertically structured vector control strategy and was so successful that sleeping sickness ceased to be considered as a major public health problem at the beginning of the 1960s. In the ensuing years sleeping sickness was largely neglected. Monitoring the disease required specialized teams that were no longer considered as cost-effective. One by one the measures that had been implemented to control the disease disappeared, thus setting the scene for a new outbreak grew. In 1995, the incidence of sleeping sickness reached the same levels as in the 1920s. The current situation is a classic example of a neglected disease with a paucity of competent specialists, diagnostic tests, effective drugs, and operational facilities. It was not until 2001 that new hope appeared thanks to a combined public- and private-sector initiative allowing restructuring of treatment teams, renovation of facilities, free distribution of drugs, and research to develop new therapeutic agents. Also thanks to the PATTEC initiative, the governments of the African affected nations are showing new in interest in sleeping sickness. However the battle is far from won and much effort will be required. Time is running out and the stakes are high.

Africa↗
PubMed2001

[Has the focus of human African trypanosomiasis in Luba, Equatorial Guinea been eradicated?].

Human African trypanosomiasis was considered a major public health problem in Luba, Equatorial Guinea in 1985. Because of the lack of qualified personnel, the emergency response consisted of a simple control strategy based on serological screening without parasitological confirmation and staging by lumbar puncture. This strategy was highly effective since the outbreak seems to have stopped. The authors discuss implications of this strategy which raises the risk of misdiagnosis and unwarranted treatment of trypanosomiasis. Other points of discussion in this article include the concept of sterilization of the disease area and need for continued low-grade surveillance.

Disease Outbreaks↗
PubMed1999

Detection of Trypanosoma brucei gambiense in sleeping sickness suspects by PCR amplification of expression-site-associated genes 6 and 7.

We have developed a sensitive and specific method to identify Trypanosoma brucei ssp. using PCR to amplify conserved expression-site-associated gene 6 and 7 DNA target sequences. Amplification of 10% of the DNA in a single trypanosome produced sufficient PCR product to be visible as a band in an agarose gel stained with ethidium bromide. We analysed 59 blood samples of serologically positive cases of sleeping sickness by PCR, and directed parasitological examination of tissue fluids. The PCR test detected 87% of the parasitologically positive cases, with a specificity of 97%. In 5 cases, the parasite was demonstrated by the PCR test 4-6 months prior to parasitological detection. This result shows the potential of the assay in early diagnosis of actual T. b. gambiense infections in apparently aparasitaemic sleeping sickness patients.

Angola↗
PubMed1999

Attitude towards CATT-positive individuals without parasitological confirmation in the African Trypanosomiasis (T.b. gambiense) focus of Quiçama (Angola).

Serologically positive individuals without parasitological confirmation constitute an important problem for trypanosomiasis control programmes because of epidemiological and therapeutical consequences. In July 1997, in the focus of Quiçama (Angola), 4753 individuals were screened using CATT/T.b.gambiense on whole blood. In CATT-positive but parasite-negative individuals, CATT titration on serum was performed. Sixteen individuals showing an end-titre lower than 1/4 were considered noninfected according to the results of a previous study of serological status of parasitologically confirmed cases; 86 individuals with end titres >/= 1/4 were considered suspected of trypanosomiasis and were followed-up from July 1997 to July 1998 with controls every three months. After one year, 32 individuals whose antibody titres dropped < 1/4 were considered noninfected, 22 were confirmed by demonstration of parasites, 17 were further followed-up because antibody titres remained >/= 1/8 but parasites could not be found. Fifteen individuals did not show up for testing. Following the usual criterion, only parasitologically confirmed cases were treated. However, if it had been decided to treat parasite-negative individuals with a CATT end-titre > 1/8, 22 initially unconfirmed but infected individuals would have been treated earlier, whereas 5 noninfected individuals would have been treated unnecessarily. CATT titration on diluted serum or plasma is useful for making therapeutical decisions.

Angola↗
PubMed1997

[Schistosoma intercalatum bilharziasis: clinical and epidemiological considerations].

Schistosoma intercalatum bilharziasis continues to raise numerous questions regarding pathogenicity and gravity. The parasite was identified recently and the last fully described outbreak occurred 10 years ago in the city of Bata, Equatorial Guinea. Geographically Schistosoma intercalatum biharziasis is limited to one part of the African continent but has shown a tendency to spread. Hybridization of Schistosoma intercalatum and Schistosoma haematobium has been observed. The main clinical manifestation of Schistosoma intercalatum is rectal bleeding. The endoscopic appearance of lesions is variable and non-specific ranging from granulomas or polyps to ulcerations. Complications include severe rectitis or genital involvement such as salpingitis with secondary sterility. Spontaneous abortion has also been reported. Association with salmonella and klebsiella infection has been confirmed and can lead to life-threatening situations. Few studies have been performed to assess the value of diagnostic tests. The sensitivity of stool smears and urinary sedimentation testing is 81.7% and 56.3% respectively using the two examinations as references for one another. The sensitivity of immunological tests is generally good but varies depending on the reference technique used. Specificity can be affected by cross-reaction with other schistosomas or trematodes and even with nematodes and hematozoons. Treatment with a single dose of Biltricide has proven to be effective. Prevention requires education of the population at risk and use of molluscacides. The control strategy must be adapted in function of the epidemiology of the disease, diagnostic data, cost and effectiveness of screening and treatment.

Abortion, Spontaneous↗
PubMed1994

Quantitative diagnosis of Schistosoma infections by measurement of circulating antigens in serum and urine.

Recent research on the detection of the schistosome circulating antigens, circulating anodic antigen (CAA) and circulating cathodic antigen (CCA), has greatly expanded the scope of applications. In the present paper aspects of assay development, in particular of highly sensitive assays and of field-applicable assays, are discussed. The progress in the use of CAA- and CCA-detection for diagnosis, follow-up of chemotherapy and sero-epidemiological studies is evaluated.

Animals↗