Fever In Endemic Areas Research Articles

Rickettsia spp. infection in Rhipicephalus sanguineus ticks in a Brazilian spotted fever endemic rural area in Rio de Janeiro state, Brazil

Rickettsia spp. infection in Rhipicephalus sanguineus ticks in a Brazilian spotted fever endemic rural area in Rio de Janeiro state, Brazil

Ecology of the Crimean-Congo Hemorrhagic Fever Endemic Area in Albania

Crimean-Congo hemorrhagic fever virus (CCHFV) is endemic in Albania. Ticks collected from cattle grazing in the endemic areas of Albania were tested for presence of CCHFV RNA, while serum samples collected from goats, cattle, hares, and birds were tested for the presence of specific IgG antibodies to CCHFV. One of the 31 pools prepared, consisting of four female Hyalomma spp. ticks, was found to carry CCHFV RNA with 99.2-100% homology to sequences detected in patients from the same region. Antibodies were not detected in cattle, hares, and birds, but 2/10 goats presented high titers of IgG antibodies. The shepherd of that flock was a member of a family affected by CCHF 10 days before the collection of goats' sera, and he presented a mild form of the disease.

Ocular Findings in Patients with Crimean-Congo Hemorrhagic Fever

To describe ocular findings of patients with Crimean-Congo hemorrhagic fever (CCHF). Prospective, interventional, consecutive case series. This study was conducted in Sivas, a city located in the central Anatolia, between July 1 and August 31, 2007. Confirmed CCHF patients were enrolled in the study and underwent ocular examination during hospitalization. Nineteen confirmed CCHF patients were included in this study. All patients were classified into 2 groups in terms of disease severity (severe vs nonsevere), according to the Swanepoel predictive criteria. Fourteen patients (73.7%) were classified as "nonsevere," and the remaining 5 patients (26.3%) were classified as "severe" in this study. One patient having severe disease died. Ocular findings were present in 14 patients (73.7%) and none of the patients presented any visual complaints. Ocular examination revealed that 7 patients (36.8%) had only bilateral multiple subconjunctival hemorrhage, and 2 patients (10.5%) (1 bilateral, 1 unilateral) had retinal hemorrhage. Five patients (26.3%) had subconjunctival hemorrhage and retinal hemorrhage. Follow-up examination 1 month later showed complete resorption of the subconjunctival hemorrhage and retinal hemorrhage. There was a statistically significant difference between patients with ocular findings and patients without ocular findings for prothrombin time (P = .011). There was no evidence of uveitis, retinal edema, sheathing of retinal vessels, or intravitreal hemorrhage in our patients. From the small sample study, CCHF caused a mild form of ocular disease. CCHF must be considered when subconjunctival or superficial retinal hemorrhages are seen in association with fever in endemic areas.

Vaccination antiamarile : mise au point à propos des effets indésirables rares et graves

Over 500 million people live in yellow fever (YF) endemic areas and more than 3 million travel to endemic countries every year. Prevention against YF, caused by the YF virus, an arbovirus, can only be efficiently obtained by active immunization. The vaccine is well tolerated and severe adverse events are very rare. Exceptionally, YF vaccination may result in serious adverse events, such as viscerotropic and neurotropic diseases, sometimes with a fatal outcome. These rare serious adverse advents are reviewed with their potential risk factors, such as advanced age or history of thymus disease. The benefit/risk ratio remains in favour of vaccination, although the decision to offer yellow fever vaccination, especially to persons 60 years of age or older, should be evaluated according to the planned trip. Additional research investigations should be made on the host immune response since this response is considered to be at the origin of these severe adverse events.

Absence of Transovarial Transmission ofBorrelia duttonii, a Tick-Borne Relapsing Fever Agent, by the Vector TickOrnithodoros moubata

We examined the vector competence of the tick, Ornithodoros moubata, using laboratory-reared gerbils as hosts. Transmission of the relapsing fever agent Borrelia duttonii occurred efficiently from infected ticks to uninfected gerbils and from infected gerbils to uninfected ticks. Spirochetes were maintained stably in the ticks for at least 3 months, but they disappeared from the bloodstream of infected gerbils after three episodes of spirochetemia. We also examined transovarial transmission of B. duttonii during the gonotrophic cycle and filial generation. No spirochetes could be detected from the offspring generation of the ticks by culture and polymerase chain reaction (PCR) methods, although spirochetes were still found in the female ticks. The results indicate that, because of the rarity of transovarial infection, the role of transovarial passage of B. duttonii to eggs and larval O. moubata ticks is limited in maintaining B. duttonii. Our findings strongly suggest that B. duttonii is maintained through the O. moubata tick-human transmission cycle in tick-borne relapsing fever endemic areas.

Enteric fever in endemic areas of Indonesia: an increasing problem of resistance

Reported levels of antibiotic resistance in Salmonella Typhi from South Sulawesi, Indonesia were very low (< 1%) before 2001 and chloramphenicol remained the treatment of choice. Since 2001 however resistance has been rising and in 2007 6.8% of isolates were resistant to all three first line drugs: Ampicillin, chloramphenicol and co-trimoxazole. Ciprofloxacin resistance is currently at 3.90 %. At the same time there has been an increase in the number of reported cases. This may be because of improved diagnostics or it may be a genuine outbreak of drug resistant S. Typhi. In conclusion drug resistant typhoid fever will become a serious problem in Indonesia in the future, requiring the use of expensive drugs for the treatment of typhoid. A concerted effort is needed by the medical services to implement reliable diagnosis so that treatment or vaccination can be used to control the spread of drug resistant typhoid fever.

Focus on yellow fever vaccination

Under International Health Regulations, vaccination is important for travel to yellow fever endemic areas. Sandra Grieve explains.

Sonographic findings of healthy volunteers infected with dengue virus

Sonography has historically been used in developing countries to help diagnose dengue infection during epidemics of dengue hemorrhagic fever in endemic areas and to predict the clinical course. In this article, we describe the sonographic findings in subjects infected with attenuated, monovalent strains of dengue virus. As part of a major research protocol to validate challenge strains of dengue virus for use in vaccines, 12 subjects were infected with 1 of 4 strains of dengue virus, and 3 subjects received placebo. The challenge was followed by an observation period. During this time, they were imaged regardless of the development of symptoms. Seven of 12 subjects infected with dengue virus showed sonographic evidence of subclinical plasma leakage, including perihepatic and perisplenic ascites, pericardial effusion, and gallbladder wall thickening. None of the 3 placebo recipients developed effusions. Sonographic evidence of fluid collection was seen in over half of subjects infected with dengue virus who did not show any evidence of dengue hemorrhagic fever. These findings shed light on possible mechanisms of plasma leakage and its role in the pathogenesis of dengue fever and dengue hemorrhagic fever.

A study of typhoid fever in five Asian countries: disease burden and implications for controls

To inform policy-makers about introduction of preventive interventions against typhoid, including vaccination. A population-based prospective surveillance design was used. Study sites where typhoid was considered a problem by local authorities were established in China, India, Indonesia, Pakistan and Viet Nam. Standardized clinical, laboratory, and surveillance methods were used to investigate cases of fever of >or= 3 days' duration for a one-year period. A total of 441,435 persons were under surveillance, 159,856 of whom were aged 5-15 years. A total of 21,874 episodes of fever were detected. Salmonella typhi was isolated from 475 (2%) blood cultures, 57% (273/475) of which were from 5-15 year-olds. The annual typhoid incidence (per 100,000 person years) among this age group varied from 24.2 and 29.3 in sites in Viet Nam and China, respectively, to 180.3 in the site in Indonesia; and to 412.9 and 493.5 in sites in Pakistan and India, respectively. Altogether, 23% (96/413) of isolates were multidrug resistant (chloramphenicol, ampicillin and trimethoprim-sulfamethoxazole). The incidence of typhoid varied substantially between sites, being high in India and Pakistan, intermediate in Indonesia, and low in China and Viet Nam. These findings highlight the considerable, but geographically heterogeneous, burden of typhoid fever in endemic areas of Asia, and underscore the importance of evidence on disease burden in making policy decisions about interventions to control this disease.

Seroepidemiología de la infección por Coxiella burnetii en donantes de sangre en Albacete

The objectives of this study were to determine the prevalence of antibodies to Coxiella burnetii among blood donors and to examine the epidemiological characteristics of C. burnetii infection in Albacete, Spain. A total of 863 serum samples were collected from blood donors aged 18-65 years. Donor samples were stratified by age, sex, and residence (rural or urban). IgG and IgM titers to the C. burnetii phase II antigen were determined by an indirect immunofluorescence assay. The prevalence of anti-phase II IgG was 23.1%, and three (0.3%) donors had positive IgM titers. Men were more frequently seropositive than women (29% vs. 18%; OR: 1.85; 95% CI: 1.34-2.56), and this difference was not related to differential occupational exposure to animals. Pet ownership had no impact on seroprevalence. In contrast, occupations involving contact with domestic ungulates were associated with a higher seroprevalence (OR: 2.39; 95% CI: 1.04-5.48). Nevertheless, 90% of seropositive donors reported no contact with farm animals. Our results show that C. burnetii infection is highly endemic in Albacete and that most infections are not linked to specific occupational exposure in this area. The high prevalence of antibodies to C. burnetii among blood donors indicates the advisability of studies to determine the risk of transfusion-transmitted Q fever in endemic areas.

Serotipo, Patrón de Infección y Dengue Hemorrágico en Área Endémica Colombiana

Describing the relationship between viral serotypes, infection pattern and dengue hemorrhagic fever. 1,545 febrile patients were studied from 1998-2004 in the Santander department of Colombia. Dengue infection was confirmed by IgM ELISA and the virus was isolated in C6/36 cells. Infection pattern was established by detecting IgG antibodies in acute serum. Neutralising antibody titres were investigated in dengue cases occurring during years when less (1998) and more (2001) dengue hemorrhagic cases were reported by using PRNT. DEN-1 predominance in 1998 and the re-introduction of DEN-3 in 2001 coincided with an epidemic. DEN-2 infection caused more hemorrhagic cases than DEN-3 infection (24,5 % cf 11,2 %; p<0.05). DEN-2 was more associated with secondary infection than DEN-3 (56,8 % cf 15,7 %; p<0.001). An annual decrease of DHF was correlated with decreased DEN-2 dominance (r=0.95; p= 0.01), and secondary infection (r=0.9; p=0.03) and increased DEN-3 predominance (r=-0.91; p=0.03). There were no differences in neutralising antibody titres amongst analysed cases. DEN-1 neutralising antibodies presented the highest titres. Change in relative dengue virus serotype abundance was associated with changed infection pattern and DHF frequency. Continuing virological surveillance should become a priority for preventing dengue hemorrhagic fever in endemic areas.

Optimizing typhoid fever case definitions by combining serological tests in a large population study in Hechi City, China

Blood culture-based diagnosis can only detect a fraction of the total burden of Salmonella enterica subsp. enterica serovar Typhi. The objective of the study was to detect additional typhoid fever cases through serological tests. A total of 1732 prolonged fever episodes were evaluated using three serological tests, Widal, Tubex and Typhidot-M in a typhoid fever endemic area of southern China. A case definition which included a positive Widal test (TO>or=80 & TH>A), a positive Tubex test (>or=4) and a positive Typhidot-M test, increased the detection of cases by more than twofold from 13 to 28 cases. The case definition has a specificity of 100% and a sensitivity of 39%. Case definitions based on combinations of serological tests can detect additional typhoid fever cases with higher specificity than a single serological test. Improved case detection is essential to understand the true disease burden and can help to boost the power of intervention trials.

Detection of Rickettsia rickettsii in the tick Amblyomma cajennense in a new Brazilian spotted fever-endemic area in the state of Minas Gerais

The present study evaluated rickettsial infection in Amblyomma spp. ticks collected in a farm in Coronel Pacheco, a Brazilian spotted fever (BSF) endemic area. A total of 78 A. cajennense and 78 A. dubitatum free-living adult ticks were collected and tested by polymerase chain reaction (PCR) targeting a fragment of the rickettsial gene gltA. Only one pool of three A. cajennense ticks showed the expected product by PCR. This pool was further tested by PCR using sets of primers targeting the rickettsial genes gltA, ompA, and ompB. All reactions yielded the expected bands that by sequencing, showed 100% identity to the corresponding sequences of the Rickettsia rickettsii gene fragments gltA (1063-bp), ompA (457-bp), and ompB (720-bp). The minimal infection rate of R. rickettii in the A. cajennense population was 1.28% (at least one infected tick within 78 ticks). The present study showed molecular evidence for the presence of R. rickettsii in A. cajennense from a BSF-endemic area in Coronel Pacheco, state of Minas Gerais. Although R. rickettsii has been previously reported infecting A. cajennense ticks in Brazil and other Latin American countries, the present study performed the first molecular characterization of R. rickettsii from the tick A. cajennense.

&lt;i&gt;In vivo&lt;/i&gt; comparison of susceptibility between &lt;i&gt;Bos indicus&lt;/i&gt; and &lt;i&gt;Bos taurus&lt;/i&gt; cattle types to &lt;i&gt;Theileria parva&lt;/i&gt; infection

The objective of this study was to determine whether Bos taurus cattle differ form Bos indicus in their susceptibility to infection with the Muguga stabilate of Theileria parva and in their resistance to the resultant disease. Ten Friesians (B. taurus), ten improved Borans (B. indicus), ten unimproved Borans (B. indicus) and ten Zebus (B. indicus) born to dams from an East Coast fever (ECF) endemic area were inoculated with an infective dose50 dilution of T. parva Muguga stabilate 147. All the animals except one Friesian and one Zebu developed schizont parasitosis. All the improved Borans, nine of the Friesians, eight of the unimproved Borans and six of the Zebus developed a febrile response. Four of the improved Borans, four of the Friesians and three of the unimproved Borans died of theileriosis. No significant difference (P > 0.05) in the prepatent period occurred between the groups, but the Zebus had a significantly shorter duration of schizont parasitosis (P > 0.05) and took a significantly shorter time to recover (P > 0.05) than the other three groups. There was no significant difference in the two parameters between the other three groups. The study showed that three B. indicus breds and a B. taurus breed are equally susceptible to T. parva infection. However, Zebus born to dams from an ECF endemic area showed a better ability to control the course of disease than cattle from ECF free areas.

Viral haemorrhagic fevers

Abstract Viral haemorrhagic fevers are viral infections that can cause shock, haemorrhage and multi-organ dysfunction. Their geographical distribution is limited by the ecology of their vectors, and many of them exist in tropical zones. The most common viral haemorrhagic fevers are not transmissible from person to person, and no viral haemorrhagic fevers are a threat to casual contacts. However, four viruses for which prevention and treatment are unreliable or not available (Crimean-Congo, Ebola, Lassa and Marburg) can be transmitted to health-care or laboratory workers. Household and health-care-related transmission is mainly limited to carers of severely ill patients, particularly patients who are highly dependent or suffering severe haemorrhage. Specialist laboratories and clinical referral centres advise on the risk assessment of suspected cases and support management of proven cases. Patients with fever after visiting viral haemorrhagic fever-endemic areas are often infected with falciparum malaria, which can cause life-threatening disease if it is not recognized and treated. Malaria should always be excluded before considering a diagnosis of viral haemorrhagic fever. If malaria or another treatable disease is not evident, or there is a definite history of direct viral haemorrhagic fever exposure, advice should be sought from an expert unit, to arrange early and safe case-management.

INVESTIGATION OF RELATIONSHIPS BETWEEN AEDES AEGYPTI EGG, LARVAE, PUPAE, AND ADULT DENSITY INDICES WHERE THEIR MAIN BREEDING SITES WERE LOCATED INDOORS

Aedes aegypti (L.) density indices obtained in a dengue fever (DF) endemic area were compared. One hundred and twenty premises, in an urban area of Colombia where dengue type-1 and type-2 virus cocirculated, were randomly selected and sampled for 7 months. The geometric mean monthly numbers (density index, DI) of Ae. aegypti eggs (ODI), 4th instar larvae (LDI), pupae (PDI), and adults (ADI) were calculated based on the use of ovitraps, nets, and manual aspirators, respectively. A negative temporal correlation was observed between the LDI and the ODI (r = -0.83, df = 5, and P < 0.01). Positive temporal correlations were only observed between the LDI and the PDI (r = 0.90, df = 5, and P < 00.5) and the Breteau and House indices (r = 0.86, df = 5, and P < 0.01). No other correlations were found between these indices and any of the other density indices or the incidence of suspected DF cases in residents, the temperature, the rainfall, or seasonal fluctuations. Our results were, therefore, probably due to the most productive Ae. aegypti breeding sites (large water containers) being located indoors within this study area. The number of adult female Ae. aegypti/person (n = 0.5) and pupae/person (n = 11) in our study area were lower and dramatically higher than the transmission thresholds previously reported for adult and pupae, respectively. Because there were confirmed DF cases during the study period, the transmission threshold based on the Ae. aegypti pupae was clearly more reliable. We found that the mean ovitrap premise index (OPI) was 98.2% during this study and that the mean larval (L-4th instars) premise index (LPI) was 59.2%, and therefore we suggest that the OPI and LPI would be more sensitive methods to gauge the effectiveness of A. aegypti control programs.

"Emerging infectious diseases". Dengue-fever, West-Nile-fever, SARS, avian influenza, HIV

ZusammenfassungNeue Infektionskrankheiten haben sich teils auch in Deutschland ausgebreitet, teils sind sie auf bestimmte Regionen der Welt begrenzt und begegnen dem Arzt nur, wenn Reisende sich in diesen Gebieten infizieren und die Krankheiten sich nach der Rückkehr manifestieren. HIV ist ein Beispiel für einen importierten, inzwischen endemischen Erreger. SARS und die aviäre Influenza sind Zoonosen, die von Tieren auf Menschen übergehen, dann aber das Potenzial haben, sich unter Menschen weiter auszubreiten. Bei aviärer Influenza spielt die Möglichkeit des Reassortment von Influenzaviren mit Entstehung eines Pandemiestamms eine besondere Rolle. Dengue-Ausbrüche in beliebten Reiseländern spiegeln sich in gehäuften Erkrankungen bei Rückkehrern wieder. West-Nil-Virus-Erkrankungen kommen derzeit nur als importierte Erkrankungen in Deutschland vor. Wichtig ist, diese Erkrankungen frühzeitig in die differenzialdiagnostischen Überlegungen des Klinikers einzubeziehen, um die erforderlichen Maßnahmen zur Diagnostik, Therapie und zum Infektionsschutz rechtzeitig einleiten zu können. Dies erfordert ein gutes Zusammenspiel mit dem Labor und dem öffentlichen Gesundheitsdienst.

Dengue fever: diagnostic importance of a camelback fever pattern

We present a case of imported dengue fever in a 52-year-old man acquired during a recent trip to Ecuador. Fever in a returning traveler from tropical areas often presents a diagnostic problem for clinicians. Our patient presented with severe arthralgias and myalgias and had a camelback/saddleback fever pattern accompanied by relative bradycardia, which was a clue to the diagnosis. He had conjunctival suffusion and the truncal rash, but adenopathy was not present. He also had a generalized headache and abdominal pain. Nonspecific laboratory abnormalities included leukopenia, lymphopenia, atypical lymphocytes, thrombocytopenia, and mildly increased serum transaminases. Clinicians should consider dengue fever in the differential diagnosis in travelers returning from dengue fever endemic areas of Southeast Asia, Latin America, and Africa. Although early findings are nonspecific, a truncal rash accompanied by leukopenia and thrombocytopenia, if followed by biphasic fever pattern (ie, camelback/saddleback fever curve with relative bradycardia), suggest dengue fever as the primary diagnostic consideration.

Detection of immunoglobulin G to Crimean-Congo hemorrhagic fever virus in sheep sera by recombinant nucleoprotein-based enzyme-linked immunosorbent and immunofluorescence assays

Crimean-Congo hemorrhagic fever virus is a tick-borne virus that causes severe hemorrhagic symptoms with an up to 50% mortality rate in humans. Wild and domestic animals, such as sheep, cattle and goats, are the reservoirs. The recombinant nucleoprotein-based Crimean-Congo hemorrhagic fever virus antibody detection systems for sheep sera were developed by enzyme-linked immunosorbent assay (ELISA) and an indirect immunofluorescence assay techniques. The samples used for evaluation were 80 sera collected from sheep in a Crimean-Congo hemorrhagic fever-endemic area (western part of the Xinjiang Uygur Autonomous Region) and 39 sera collected from sheep in a disease-free region (Shandong province, eastern China). The ELISA and indirect immunofluorescence assay using recombinant nucleoprotein of the virus proved to have high sensitivity and specificity for detecting the immunoglobulin G antibodies to the virus in sheep sera. Within this limited number of samples, the recombinant nucleoprotein-based ELISA and indirect immunofluorescence assay are considered to be useful tools for seroepidemiological study of virus infections in sheep sera.

Identification of Clinical Criteria for Group A- Hemolytic Streptococcal Pharyngitis in Children Living in a Rheumatic Fever Endemic Area

A cross-sectional study was conducted over a 1-year period (1 January-31 December 2000) during which cases suffering from uncomplicated tonsillopharyngitis were recruited from the private and public health services in Alexandria. The objective was to determine the prevalence of group A-beta haemolytic streptococci (GABHS) among children suffering from tonsillopharyngitis and to identify the clinical criteria predicting GABHS pharyngitis in children. A total of 578 children aged between 1 and 15 years with a mean of 6.3 +/- 3.7 years, presenting with sore throat were enrolled in the study. Demographic data and presenting signs and symptoms for each patient were recorded on a standardized form and a throat swab was taken using the filter paper technique. The overall prevalence of GABHS was 17 per cent and the highest isolation rate was reported in children aged 10-15 years. Non-GABHS comprised 11.9 per cent of the total isolates. The most prevalent of them were group C and G streptococci. The highest frequency of both GABHS and non-GABHS was in early spring. Significant predictors of GABHS pharyngitis were: age 10-15 years, the presence of dysphagia, vomiting, pharyngeal exudate, and scarlatiniform rash. Watery eyes and/or rhinitis had a protective value against the diagnosis of GABHS pharyngitis, while fever was considered to be a non-specific finding in cases with GABHS pharyngitis. Antibiotic sensitivity test showed higher sensitivity to both penicillin and erythromycin. Only 1 per cent of the GABHS isolates showed resistance to cephadroxil. We concluded that a syndrome of signs and symptoms could be used as a clinical predictor for the diagnosis of GABHS pharyngitis.