Understanding the reasons for decline of HIV prevalence in Haiti.

OBJECTIVES: HIV sero-surveillance rounds and projection estimates suggest a decline of HIV prevalence among pregnant women and the general population in Haiti. This study aimed to evaluate the decline of HIV prevalence and understand the reasons for the decline. METHODS: Following an epidemiological analysis, three mathematical models were used to re-create the national epidemic, calculate HIV incidence, and confirm the decline of HIV prevalence. Declining trends in prevalence data were compared with observed trends in behavioural data. RESULTS: HIV progressed rapidly from initial infection to AIDS and death, with people dying twice as fast as in developed countries. With the rapid progression of the disease and the early intervention efforts in securing the blood supply, prevalence among commercial sex workers and blood donors peaked in the late 1980s followed by a decline in the mid-1990s in the general population. The observed decline among pregnant women and in the general population was confirmed after controlling for confounding variables. The Haitians are well informed: there is an increase in condom use with occasional partners at last contact and in abstinence and fidelity, and a decrease in the number of occasional partners. However, the age of sexual debut is lower and the proportion of sexually active youth has increased. CONCLUSIONS: There is evidence of decline in HIV prevalence among pregnant women, specifically among pregnant women living in urban areas and pregnant women 25 years and older, but not among pregnant women living in rural areas and pregnant women 24 years and younger. Although many factors have acted in synergy to halt the AIDS epidemic in Haiti, the main reasons for decline seem to point to mortality and blood safety intervention efforts in the early stages of the epidemic.

Declines in HIV prevalence can be associated with changing sexual behaviour in Uganda, urban Kenya, Zimbabwe, and urban Haiti.

OBJECTIVE: To determine whether observed changes in HIV prevalence in countries with generalised HIV epidemics are associated with changes in sexual risk behaviour. METHODS: A mathematical model was developed to explore the relation between prevalence recorded at antenatal clinics (ANCs) and the pattern of incidence of infection throughout the population. To create a null model a range of assumptions about sexual behaviour, natural history of infection, and sampling biases in ANC populations were explored to determine which factors maximised declines in prevalence in the absence of behaviour change. Modelled prevalence, where possible based on locally collected behavioural data, was compared with the observed prevalence data in urban Haiti, urban Kenya, urban Cote d'Ivoire, Malawi, Zimbabwe, Rwanda, Uganda, and urban Ethiopia. RESULTS: Recent downturns in prevalence observed in urban Kenya, Zimbabwe, and urban Haiti, like Uganda before them, could only be replicated in the model through reductions in risk associated with changes in behaviour. In contrast, prevalence trends in urban Cote d'Ivoire, Malawi, urban Ethiopia, and Rwanda show no signs of changed sexual behaviour. CONCLUSIONS: Changes in patterns of HIV prevalence in urban Kenya, Zimbabwe, and urban Haiti are quite recent and caution is required because of doubts over the accuracy and representativeness of these estimates. Nonetheless, the observed changes are consistent with behaviour change and not the natural course of the HIV epidemic.

Detection of coproantigen in early trichinellosis.

Trichinellosis has become undoubtedly worldwide in distribution. Its diagnosis relies largely on the serodiagnostic procedures which are of great value but unfortunately miss the enteric phase. This could be a serious diagnostic problem in the absence of corresponding epidemiological data and typical symptoms and signs of the disease. In this study the possibility of coproantigen detection, as an early diagnostic aid in trichinellosis, was investigated in mice experimentally infected with Trichinella spiralis. A modified double sandwich ELISA was developed using polyclonal antibodies raised in rabbits and guinea pigs against larval somatic antigens. The first detection of coproantigen was as early as the first day post infection, gradually increasing to reach its peak on the seventh day and then decreasing to disappear completely on the third week post infection. Another test, the coagglutination test (Co-A) was used, and this test confirmed the previous results. The finding of this study suggest that the coproantigen detection could be exploited to confirm ongoing early Trichinella spiralis infection. This fast and easy to use diagnostic method should improve the early infection in human.

Effects of caregiver specialty on cost and clinical outcomes following hospitalization for heart failure.

In 614 consecutive hospitalizations with the primary discharge diagnosis of diagnosis-related group (DRG) 127 (heart failure and shock), we sought to assess the effect of caregiver specialty (generalist, n = 217; cardiologist, n = 397) on hospital costs, length of stay, and in-hospital mortality. Patients treated by cardiologists were younger (68 vs 71 years) and less likely to have hypertension (52% vs 61%), but were more likely to be men (61% vs 44%), require an intensive care stay (13% vs 5%), have coronary artery disease (49% vs 23%), have a left ventricular ejection fraction <40% (74% vs 49%), and have lower systolic (132 vs 146 mm Hg) and diastolic (76 vs 81 mm Hg) blood pressures on admission. Predictors of acute disease severity were similarly distributed between the 2 groups. No difference was found between patients treated by cardiologists versus those treated by generalists with respect to crude or adjusted hospital cost, length of stay, and in-hospital mortality. However, in subsets of patients who required intensive care during hospitalization (n = 64), as well as those who did not (n = 550), care by cardiologists was associated with a lower adjusted hospital cost. Any potential cost savings that could have accrued from care by cardiologists was, however, negated by the higher proportion of patients treated by cardiologists who required intensive care during hospitalization. We conclude that when differences in clinical variables are adjusted, care by cardiologists versus generalists is associated with similar or lower hospital cost for patients with DRG 127. Our findings challenge the notion that in-patient care provided by specialists is more expensive than that provided by generalists.

Role of anti-Trichinella spiralis antibodies and interferon-gamma in the protection against the enteral phase of experimental trichinosis.

Expulsion of adult Trichinella spiralis is the result of a complex immunologically mediated response. Experiments in mice demonstrated that IFN-gamma, released by mesenteric lymph nodes (MLN) during infection play a major role. However, the role of mucosal and serum antibody responses is thought to be limited. Working on the intestinal phase, this study investigated, the role played by antibodies, transferred from vaccinated infected animals, in the immune response in comparison to that obtained by IFN-gamma administration. Transfer of antibodies gave 82.7% protection, while IFN-gamma in a dose of 1 x 10(4) U gave 98.4% protection. The use of half the previous dose induced a protection of 58.3%. These data indicate that vaccination followed by infection could generate antibodies capable of producing a protective immune response against the intestinal phase of T. spiralis. This reached a level near to that obtained by IFN-gamma administration.

Clinical variables affecting recovery of left atrial mechanical function after cardioversion from atrial fibrillation.

OBJECTIVES: We sought to evaluate the effect of clinical factors on recovery of atrial function after cardioversion for atrial fibrillation. BACKGROUND: Lack of effective mechanical atrial function (EMAF) after cardioversion of atrial fibrillation predisposes to thromboembolic complications and delays improvement in functional capacity. METHODS: Fifty-two patients underwent cardioversion (group I, electrical cardioversion, n = 40; group II, pharmacologic or spontaneous cardioversion, n = 12) for atrial fibrillation. Serial transmitral inflow Doppler variables were recorded after cardioversion until EMAF (atrial filling velocity > 0.50 m/s) was seen. Clinical variables (age, duration of atrial fibrillation, left ventricular ejection fraction, left atrial diameter, underlying cardiovascular disease, antiarrhythmic drug therapy and mode of cardioversion) were tested for an association with the outcomes of recovery of atrial function by day 3 and day 7. RESULTS: Effective mechanical atrial function recovered in 68% of patients by day 3 and in 76% by day 7 after cardioversion. The mode of cardioversion was significantly associated with recovery of atrial function by day 3 in bivariate and multivariate analyses (odds ratio 0.12, 95% confidence interval 0.01 to 1.0, for electrical cardioversion). None of the variables had an association with recovery of atrial function by day 7. Group I patients took a longer time to recover atrial function than group II patients (p = 0.012). In addition, group I patients had a significantly lower peak atrial filling velocity (mean [+/-SD] 0.39 +/- 0.19 m/s vs. 0.56 +/- 0.16 m/s) and a higher early filling to atrial filling velocity ratio (2.5 +/- 1.2 vs. 1.5 +/- 0.5) after cardioversion. CONCLUSIONS: A high proportion of patients recover EMAF within 1 week after cardioversion. Patients who undergo electrical cardioversion display a greater degree and a longer duration of mechanical atrial dysfunction than those who convert pharmacologically or spontaneously.

Detection of Trichinella pseudospiralis antigen in the parenteral phase in experimentally infected mice.

Antigen distribution of T. pseudospiralis in muscles was studied at 10 days, 2,3 and 5 weeks post infection. Immunocytolocalization of antigen in the muscle was performed by peroxidase antiperoxidase (PAP) and immunogold silver staining techniques. Weak positive reaction of the stichosome and the cuticle was observed at 10 days post-infection which increased to attain its highest level in the fully infective stage larvae 3 and 5 weeks post infection. The intensity of staining reaction in the cytoplasm and nucleoplasm of infected host cell and surrounding tissue was highest at 5 weeks p.i. The small nuclei of the host cells and the inflammatory cells were unstained.

Detection of circulating Trichinella pseudospiralis antigen by enzyme linked immunosorbant assay (ELISA).

A modified double antibody sandwich ELISA was used as a sensitive technique for demonstrating the appearance of circulating antigen of T. pseudospiralis in the sera of infected mice. The sera were tested at 5 days, 2, 4, 6, 7, 8, 10 and 12 weeks P.I. The antigen was first detected on the 5th day P.I., its level increased to reach the 1st peak at 4 weeks, then declined at 6 weeks. A second peak was observed at 8th weeks followed by a sharp decline to give negative OD reading at 10th week and increased to a moderate level at 12 weeks P.I.

Detection of Trichinella pseudospiralis antigen in the enteral phase in experimentally infected mice.

The distribution of T. pseudospiralis antigen in tissue sections of the intestine of infected mice was studied at different intervals (10, 21, 35 hours and 10 days post-infection (P.I.). Immunocytolocalization of antigen in the intestine was done by peroxidase antiperoxidase staining technique. Positive staining reaction of the enterocytes was noted in all durations examined. The mononuclear cells of the lamina propria were positively stained at 10 hrs P.I. while patchy staining of muscularis mucosa was observed at 10 days P.I. The present study revealed intense staining reaction in the stichosome and the cuticle of 10 hrs-old larvae L1, the intensity of the reaction decreased throughout the worm development, until it almost disappeared at 10 days P.I. The gut lining and its occupying substance were positive throughout the enteral phase. Intense staining reaction of the hypodermal cells was observed in L2, L3 and adult stage worm. The genital primordium was weakly stained in the larval stages while the male and female reproductive systems were moderately stained at the adult stage.

Scanning electron microscopic study of Trichinella pseudospiralis muscle phase after modulation of host response using an immunostimulant drug.

In a previous study, evident collagen deposition around T. pseudospiralis larvae was noticed after administration of Levamisole to infected mice. The present investigation was undertaken to confirm these findings. Scanning electron microscopic examination revealed multiple clear cystic formations on the surface of the diaphragm muscle. The present investigation was undertaken to confirm these findings. Scanning electron microscopic examination revealed multiple clear cystic formations on the surface of the diaphragm muscle. The presence of such structures was seen to be more frequent when the drug was given as early as the 6th day post infection. Membrane like structure was observed around T. pseudospiralis larvae, an interesting finding which was by far not reported before.

Modulation of host response during infection with Trichinella pseudospiralis using immuno-stimulant drug.

Infection of the mouse with Trichinella pseudospiralis is accompanied by pronounced suppression of host inflammatory response. This study examines the effect of infection with this parasite on one major component of cell mediated immunity: delayed type hypersensitivity (DTH) reaction and the effect of administration of immunostimulant drug (Levamisole) on host response to T. pseudospiralis infection. Serum cortisol levels and the response of skin test to phytohaemagglutinin were used to construct the time table of drug regimen. Three groups were studied; group I (infected mice), group II (received levamisole on day 6 p.i.) and group II (received Levamisole on day 14 p.i.) Early administration of Levamisole restored DTH response to normal and histopathological examination of infected muscles revealed evident collagen deposition around the muscle larvae.

Studies on T. spiralis and T pseudospiralis larvae recovered from mice immunized with heterologous Trichinella antigen.

In this study, S3 antigen of T. spiralis and T. pseudospiralis was given to the heterologous infection in albino mice. The recovered larvae were studied as regards: their number, length and steroscan examination. It was found that vaccination of mice with T. spiralis (S3) antigen induced reduction in T. pseudospiralis larval count by 66.43% and significant reduction in length. Using T. pseudospiralis (S3) antigen reduction of 74.77% in T. spiralis larval count was detected as well as significant reduction in length. Scanning electron microscopic (SEM) examination revealed more or less similar finding in both species: loss of integrity of the cuticle, some of the larvae were attacked by granulocytes mainly eosinophils and few larvae appeared completely destructed with loss of normal architecture. A peculiar finding was noticed in case of T. pseudospiralis larvae in form of fine electron dense deposits giving the cuticular surface a motling appearance.

Determining the prevalence of neurosyphilis in a cohort co-infected with HIV.

A retrospective study of 767 HIV positive patients from a large urban public hospital, 238 of whom were co-infected with syphilis, was performed to determine the prevalence of neurosyphilis. A prevalence of 3% of neurosyphilis in the co-infected cohort was demonstrated. The 7 cases of neurosyphilis ascertained were of the early stage variety, with cranial nerve involvement the predominant focal deficit. Of the 5 cases presenting after initial diagnosis and treatment of syphilis, 4 were felt to be inadequately treated. An overall prevalence of 1% (7/767) was determined for the entire HIV(+) cohort. The majority of the cases of syphilis (90%) were characterized as latent syphilis. Based on these findings, the authors recommend routine CSF examination in all patients who are HIV positive and who present with latent syphilis. Treatment regimens should be maximized in an effort to reduce the prevalence of neurosyphilis in such a co-infected cohort.

Cyclosporin A in experimental trichinosis scanning electron microscopic study.

The surface morphology of adult and larvae of Trichinella spiralis after cyclosporin A treatment was studied by scanning electron microscopy (SEM) of fixed, dried and metal coated specimens. The earliest topographic changes revealed in adults after the drug treatment were in form of disorganization of the cuticle especially between the hypodermal pores which appeared somewhat thickened and irregular. Other changes were in form of bullae formation covering the whole width of the adult surface. Other specimens showed wrinkling of the outer layer that was seen later to peel off. In few worms layer outer was damaged releasing some of the internal organs. Smoothing of the cuticle with obliteration of the grooves between the cuticular ridges were observed as the earliest surface larval changes, ulcer formation which was deeply seated was seen in patchy areas in some specimens. The interaction between the parasite surface and the drug is of significant importance as this can throw light on the possibilities of its mode of action.

Heterophyids: experimental chemotherapy and immunotherapy.

Heavy infections with the tiny flukes heterophyids can cause intestinal pain and mucous diarrhea, thus the study of praziquantel (Pzq) and the new drug cyclosporin A (CsA) as antiparasitic drugs were undertaken in this work, as well as the effect of matecercarial and adult antigens as immunizing agents. To assess the result of our work, the number and length of the recovered heterophyids were studied. Description of the surface by SEM was carried out for the groups: treated by cyclosporin A and immunized by adult heterophyid antigen (third fraction) which gave the highest percentage reduction.

Cyclosporin A in experimental trichinosis: histopathological study.

Cyclosporin A (CsA), a relatively new drug, was previously used in a series of studies on experimental trichinosis. This work was conducted to study the histopathological changes of CsA treatment at different time intervals from T. spiralis infection in mice. The work included study of the effect of the drug on the larvae treated either in vivo or in vitro. The drug was most effective when it was administered on the same day of infection, then when given one week before. The effect was evidenced by diminution both in the number of larvae and in the cellular reactions.

Effect of cyclosporin A on trichinosis. A histochemical study.

The aim of this work was to reveal the possible effect of the drug CSA treatment in experimental trichinosis on some important tissue enzymes; alklline and acid phosphatases, succinic dehydrogenase and alpha-esterase. This study revealed that the effect of the drug was apparently evident on succinic dehydrogenase enzyme which returns back to the control. The diminished acid phosphatase activity showed the effect of the drug on the T-cells.

Cyclosporin A in experimental trichinosis; parasitological study.

During the last few years, antiparasitic effects has been related to the immunosuppressant cyclosporin A (CsA). This work was planned to study the effect of this drug against different aspects of experimental trichinosis. The work included three experiments. The first experiment was to study the effect of (CsA) on infection when administered to mice at different durations i.e. post infection as well as before and on the same day of infection. It proved to be most effective when given on the same day of infection as evidenced by the significant reduction in adult count, length of female, larval count and index of reproductive capacity (RCI). However, the effect though still significant, diminished when the drug was given pre- and post-infection. The second experiment was to study the effect of (CsA) on infectivity of the T. spiralis larvae treated either in vivo or in vitro. The results showed that the drug has marked effect in that part of the study as shown by the reduction in all parameters of assessment. The third experiment demonstrated the challenge that followed (CsA) treated primary compared to that of non treated one. Results showed significant reduction in all values. These results evoke ideas for further designs of other treatment and control strategies for the disease.

Childhood survival in Haiti: protective effect of measles vaccination.

To evaluate the impact of measles vaccination on survival of children residing in a periurban slum in Haiti, a total-population survey was conducted 2.5 years after completion of a one-time study of the serologic response to measles vaccine administered in the same population. Pregnancy histories from the 16,400 women in the population revealed that 1499 children had been born during a 7-month interval that would have made them eligible for participation in the measles vaccine program. Of these children, 1381 (92.1%) survived to 9 months of age, the median age that measles vaccine had been administered. Seventy-three infants had died between 9 and 39 months of age. Mortality of infants who were seronegative before receiving measles vaccine was significantly lower (P = .0013) than that of unvaccinated infants (3/235 vs 70/1056, respectively). Other factors positively associated with survival between 9 and 39 months of age included socioeconomic status (P = .0002), maternal literacy (P = .0020), maternal knowledge and use of oral rehydration solution (P = .0002), and an interval of greater than 24 months to the birth of the next younger sibling (P = .0012). Multivariate stepwise logistic regression analysis was used to evaluate the independent association of measles vaccination by adjusting for other factors that also correlated with survival and that might have been associated with maternal seeking of vaccinations.(ABSTRACT TRUNCATED AT 250 WORDS)

Preparation and use of monoclonal antibodies in the detection of Trichinella spiralis circulating antigen.

In the present study, a trial was made to evaluate the monoclonal antibody produced as a tool in the detection of circulating antigen. For the preparation of monoclonal antibodies, four Balb/C mice were immunized with Trichinella spiralis larvae. Immunized spleen cells were prepared and a suitable mutant NS1 myeloma cell line was used for fusion. Eighty white swiss albino mice were orally infected with 500 L1 T. spiralis larvae. Their serum was collected at different periods i.e. 5, 11, 18 and 28 days post infection for the detection of circulating antigen which was done by the ELISA technique. Circulating antigen could not be detected on day 5 post infection, while on day 11 it was clearly identified; on day 18 it could be detected but at a lesser O.D. reading however the antigen disappeared completely on the 28th day. This study confirmed that monoclonal antibodies may be a valuable tool in the early diagnosis of trichinosis by the detection of specific antigens, even in small amounts whenever present in the circulation.