Rodent-borne infections in rural Ghanaian farming communities

Rodents serve as reservoirs and/or vectors for several human infections of high morbidity and mortality in the tropics. Population growth and demographic shifts over the years have increased contact with these mammals, thereby increasing opportunities for disease transmission. In Africa, the burden of rodent-borne diseases is not well described. To investigate human seroprevalence of selected rodent-borne pathogens, sera from 657 healthy adults in ten rural communities in Ghana were analyzed. An in-house enzyme-linked immunosorbent assay (ELISA), for immunoglobulin G (IgG) antibodies to Lassa virus was positive in 34 (5%) of the human samples. Using commercial kits, antibodies to hantavirus serotypes, Puumala and Dobrava, and Leptospira bacteria were detected in 11%, 12% and 21% of the human samples, respectively. Forty percent of residents in rural farming communities in Ghana have measurable antibodies to at least one of the rodent-borne pathogens tested, including antibodies to viral hemorrhagic fever viruses. The high seroprevalence found in rural Ghana to rodent-borne pathogens associated with both sporadic cases and larger disease outbreaks will help define disease threats and inform public health policy to reduce disease burden in underserved populations and deter larger outbreaks.

Serosurvey for zoonotic viral and bacterial pathogens among slaughtered livestock in Egypt

INTRODUCTION

Zoonotic diseases are an important cause of human morbidity and mortality. Animal populations at locations with high risk of transmission of zoonotic pathogens offer an opportunity to study viral and bacterial pathogens of veterinary and public health concern.

METHODS

Blood samples were collected from domestic and imported livestock slaughtered at the Muneeb abattoir in central Egypt in 2009. Samples were collected from cattle (n=161), buffalo (n=153), sheep (n=174), and camels (n=10). Samples were tested for antibodies against Leptospira spp. by a microscopy agglutination test, Coxiella burnetii by enzyme immunoassay, Brucella spp. by standard tube agglutination, and Rift Valley Fever virus (RVFV), Crimean-Congo hemorrhagic fever virus (CCHFV), sandfly fever Sicilian virus (SFSV), and sandfly fever Naples virus (SFNV) by enzyme-linked immunosorbent assay.

RESULTS

Antibodies against Leptospira spp. were identified in 64 (40%) cattle, 45 (29%) buffalo, 71 (41%) sheep, and five (50%) camels; antibodies against C. burnetii in six (4%) buffalo, 14 (8%) sheep, and seven (70%) camels; and antibodies against Brucella spp. in 12 (8%) cattle, one (1%) buffalo, seven (4%) sheep, and one (10%) camel. Antibodies against RVFV were detected in two (1%) cattle and five (3%) buffalo, and antibodies against CCHFV in one (1%) cow. No antibodies against SFSV or SFNV were detected in any species.

DISCUSSION

RESULTS indicate that livestock have been exposed to a number of pathogens, although care must be taken with interpretation. It is not possible to determine whether antibodies against Leptospira spp. and RVFV in cattle and buffalo are due to prior vaccination or natural exposure. Similarly, antibodies identified in animals less than 6 months of age may be maternal antibodies transferred through colostrum rather than evidence of prior exposure. RESULTS provide baseline evidence to indicate that surveillance within animal populations may be a useful tool to monitor the circulation of pathogens of veterinary and public health concern in Egypt.

Detection of Dobrava hantavirus RNA in Apodemus mice in Bulgaria

Several Hantaviruses cause hemorrhagic fever with renal syndrome (HFRS) in Europe: Dobrava-Belgrade virus (DOBV), Puumala, Saaremaa, Sochi, and Seoul virus. Although HFRS is endemic in Bulgaria, genome sequences of hantaviruses have never been detected in wild rodents. To identify rodent reservoirs, a total of 691 rodents from three endemic regions were trapped in 2011-2012 and screened by TaqMan RT-PCR for detection of hantaviral genomic RNA. Partial small (S) and/or large (L)-segment sequences were recovered from six Apodemus mice: five of the species A. flavicollis and one A. agrarius. Phylogenetic analysis revealed that all recovered sequences belonged to DOBV. On the phylogenetic trees, the novel Bulgarian hantavirus sequences clustered together with sequences of established previously DOBV variants recovered from Bulgarian HFRS patients and also with variants found in wild rodents trapped in Slovenia, Greece, and Slovakia. One of the novel Bulgarian DOBV S-sequences from A. agrarius was related closely to DOBV sequences recovered from A. flavicollis, suggesting a spillover of DOBV from its natural host to A. agrarius mice. The results of this study confirmed the circulation of DOBV in wild rodents in Bulgaria. The complexity of the epidemiological situation in the Balkans requires further studies of hantaviruses in rodent hosts and human HFRS cases.

Seroprevalance of Crimean-Congo haemorrhagic fever in Bulgarian livestock

Crimean–Congo haemorrhagic fever (CCHF) is a tick-borne zoonotic disease. Over the past decade, CCHF cases in humans have emerged in Turkey and reemerged in the Balkan countries, Ukraine and Tajikistan. Occupational contact with infected livestock has been recognized as a common cause of the disease. A cross-sectional seroprevalence study in livestock was conducted in farming communities of an endemic area in Bulgaria, southeastern Europe. Overall, 72% of the tested animals were positive for IgG antibodies to CCHF virus. By the time the animals were one-year old almost 50% had serologic evidence of CCHF infection, and by two years already 80% of them had been infected. The data obtained in this study reflect current situation of CCHF virus infection among livestock in Bulgaria. The results showed active CCHF virus circulation that poses risk for humans to be infected during contacts with animals and requires public health awareness.

Chikungunya outbreak in Al-Hudaydah, Yemen, 2011: epidemiological characterization and key lessons learned for early detection and control

Little is known about the occurrence of chikungunya fever in the Eastern Mediterranean Region of the World Health Organization (WHO). In January 2011, the Ministry of Public Health and Population (MoPH&P) of Yemen reported to WHO an increasing number of “dengue-like” acute febrile illnesses of unknown origin from one of its coastal governorates. An epidemiological investigation was conducted in Al-Hudaydah governorate between 23 and 26 January 2011 by a joint team of WHO, the MoPH&P of Yemen and the U.S. Naval Medical Research Unit (NAMRU-3) in Cairo, Egypt. The investigation led to the detection of an outbreak of chikungunya in Yemen which was the first time ever from any of the 22 countries in the Eastern Mediterranean Region of WHO. Appropriate public health control measures were strengthened following the investigation, and the outbreak was contained. This paper provides a short description of the outbreak and its epidemiological characteristics and highlights the important lessons that were learned for early detection and control of chikungunya in countries where competent vectors for transmission of the virus exist.

Tick-borne encephalitis in Bulgaria, 2009 to 2012

For the last 60 years, only a few cases of tick-borne encephalitis (TBE) have been detected in Bulgaria. Considering the remarkable increase in TBE morbidity in Europe over the past two decades, we conducted a study of TBE among patients with acute viral meningitis who were hospitalised in Bulgaria during 2009 to 2012. A total of 86 patients with viral meningitis of unknown aetiology during this period were tested. Acute TBE was confirmed in three of these patients. The last TBE case was detected in October 2012; the other two were diagnosed in 2009. To the best of our knowledge, these three patients are the first confirmed TBE cases reported in Bulgaria. The risk of TBE is underestimated in Bulgaria due to the low awareness of medical doctors.

Seroepidemiologic survey for Coxiella burnetii among US military personnel deployed to Southwest and Central Asia in 2005

We used a seroepidemiologic study to estimate Q fever (Coxiella burnetii) seroprevalence, seroincidence, and risk factors for seroconversion in two deployed military populations in 2005. The first study group resided in an area with a known Q fever outbreak history (Al Asad, Iraq). Of this population, 7.2% seroconverted for an incidence rate of 10.6 seroconversions per 1,000 person-months. The second population included personnel transiting through Qatar on mid-deployment leave from southwest/central Asia. In this group, we found 2.1% prevalence with 0.92 seroconversions per 1,000 person-months. However, no significant risk factors for Q fever seroconversion were found in either population.

A high diversity of Eurasian lineage low pathogenicity avian influenza A viruses circulate among wild birds sampled in Egypt

Surveillance for influenza A viruses in wild birds has increased substantially as part of efforts to control the global movement of highly pathogenic avian influenza A (H5N1) virus. Studies conducted in Egypt from 2003 to 2007 to monitor birds for H5N1 identified multiple subtypes of low pathogenicity avian influenza A viruses isolated primarily from migratory waterfowl collected in the Nile Delta. Phylogenetic analysis of 28 viral genomes was performed to estimate their nearest ancestors and identify possible reassortants. Migratory flyway patterns were included in the analysis to assess gene flow between overlapping flyways. Overall, the viruses were most closely related to Eurasian, African and/or Central Asian lineage low pathogenicity viruses and belonged to 15 different subtypes. A subset of the internal genes seemed to originate from specific flyways (Black Sea-Mediterranean, East African-West Asian). The remaining genes were derived from a mixture of viruses broadly distributed across as many as 4 different flyways suggesting the importance of the Nile Delta for virus dispersal. Molecular clock date estimates suggested that the time to the nearest common ancestor of all viruses analyzed ranged from 5 to 10 years, indicating frequent genetic exchange with viruses sampled elsewhere. The intersection of multiple migratory bird flyways and the resulting diversity of influenza virus gene lineages in the Nile Delta create conditions favoring reassortment, as evident from the gene constellations identified by this study. In conclusion, we present for the first time a comprehensive phylogenetic analysis of full genome sequences from low pathogenic avian influenza viruses circulating in Egypt, underscoring the significance of the region for viral reassortment and the potential emergence of novel avian influenza A viruses, as well as representing a highly diverse influenza A virus gene pool that merits continued monitoring.

Microevolution of highly pathogenic avian influenza A(H5N1) viruses isolated from humans, Egypt, 2007-2011

We analyzed highly pathogenic avian influenza A(H5N1) viruses isolated from humans infected in Egypt during 2007-2011. All analyzed viruses evolved from the lineage of subtype H5N1 viruses introduced into Egypt in 2006; we found minimal evidence of reassortment and no exotic introductions. The hemagglutinin genes of the viruses from 2011 formed a monophyletic group within clade 2.2.1 that also included human viruses from 2009 and 2010 and contemporary viruses from poultry; this finding is consistent with zoonotic transmission. Although molecular markers suggestive of decreased susceptibility to antiviral drugs were detected sporadically in the neuraminidase and matrix 2 proteins, functional neuraminidase inhibition assays did not identify resistant viruses. No other mutations suggesting a change in the threat to public health were detected in the viral proteomes. However, a comparison of representative subtype H5N1 viruses from 2011 with older subtype H5N1 viruses from Egypt revealed substantial antigenic drift.

Crimean-Congo hemorrhagic fever, Afghanistan, 2009

In response to an outbreak of Crimean-Congo hemorrhagic fever in western Afghanistan, we measured immunoglobulin G seroprevalence among household members and their animals. Seroprevalence was 11.2% and 75.0% in humans (n = 330) and livestock (n = 132), respectively. Persons with frequent exposure to cattle had an elevated risk of being immunoglobulin G positive.

Effects of hand hygiene campaigns on incidence of laboratory-confirmed influenza and absenteeism in schoolchildren, Cairo, Egypt

To evaluate the effectiveness of an intensive hand hygiene campaign on reducing absenteeism caused by influenza-like illness (ILI), diarrhea, conjunctivitis, and laboratory-confirmed influenza, we conducted a randomized control trial in 60 elementary schools in Cairo, Egypt. Children in the intervention schools were required to wash hands twice each day, and health messages were provided through entertainment activities. Data were collected on student absenteeism and reasons for illness. School nurses collected nasal swabs from students with ILI, which were tested by using a qualitative diagnostic test for influenza A and B. Compared with results for the control group, in the intervention group, overall absences caused by ILI, diarrhea, conjunctivitis, and laboratory-confirmed influenza were reduced by 40%, 30%, 67%, and 50%, respectively (p<0.0001 for each illness). An intensive hand hygiene campaign was effective in reducing absenteeism caused by these illnesses.

Studies on West Nile virus infection in Egypt

We conducted a prospective cohort study to determine prevalence and incidence of West Nile virus (WNV) in Egypt. Cohorts were established in Upper (UE), Middle (ME), and Lower (LE) Egypt. Additionally, a cross-sectional serosurvey was performed in the North (NS) and South (SS) Sinai. Cohorts were bled initially and 1 year later. Sera were tested for WNV-IgG by ELISA and positive sera were confirmed by plaque reduction neutralization test (PRNT). Sentinel chicken flocks placed in the above sites were bled monthly for virus isolation and serology. Mosquitoes were collected monthly from the above sites and tested for WNV. Human seroprevalence rates were 35%, 27%, 14%, 1% and 7% in UE, ME, LE, NS and SS, respectively. Seroconversion rates were 18%, 17% and 7% in UE, ME and LE, respectively; 49% of the seroconverters reported undiagnosed febrile illness. Sentinel chickens showed seroconversion in all study sites. WNV was isolated from both sentinel chickens and mosquitoes in cohort sites. This study demonstrates that WNV was actively circulating during the study period in different areas in Egypt and causing febrile illness in a considerable proportion of individuals in the study sites.

Outbreak of sandfly fever in central Iraq, September 2007

An outbreak of nonspecific febrile illnesses occurred among U.S. Army troops in September 2007 at a remote, newly established, rural-situated patrol base, south of Baghdad, Iraq. Soldiers displayed an acute flu-like syndrome with symptoms of fever, headache, malaise, and myalgia. A total of 14 cases was identified and treated presumptively as query fever. Subsequent convalescent serum specimens confirmed 13 (92.9%) positive for sandfly Sicilian virus and 3 (21.4%) positive for Coxiella burnetii, with two positive for both. One sandfly Sicilian virus case tested positive for Brucella spp. This outbreak emphasizes the potential for multiple simultaneous disease exposures to endemic diseases in nonindigenous military personnel at remote military locations in Iraq. Recommendations include increased theater disease surveillance, medical training, and vector control.

Inactivation of microbes using ultrasound: a review

Alternative methods for pasteurization and sterilization are gaining importance, due to increased consumer demand for new methods of food processing that have a reduced impact on nutritional content and overall food quality. Ultrasound processing or sonication is one of the alternative technologies that has shown promise in the food industry. Sonication alone is not very effective in killing bacteria in food; however, the use of ultrasound coupled with pressure and/or heat is promising. Thermosonic (heat plus sonication), manosonic (pressure plus sonication), and manothermosonic (heat and pressure plus sonication) treatments are likely the best methods to inactivate microbes, as they are more energy-efficient and effective in killing microorganisms. Ultrasonic processing is still in its infancy and requires a great deal of future research in order to develop the technology on an industrial scale, and to more fully elucidate the effect of ultrasound on the properties of foods.

Seroprevalence of West Nile, Rift Valley, and sandfly arboviruses in Hashimiah, Jordan

We conducted a serosurvey among patients of a health center in Hashimiah, a Jordanian town of 30,000 inhabitants located near a wastewater treatment plant and its effluent channel. Serum samples from 261 patients >/=5 years of age were assessed for immunoglobulin G (IgG) and IgM antibodies against West Nile, sandfly Sicilian, sandfly Naples, and Rift Valley viruses; the seroprevalence of IgG antibodies was 8%, 47%, 30%, and 0%, respectively. Female participants were more likely to have been infected than male. Persons living within 2 km of the treatment plant were more likely to have been infected with West Nile (p=0.016) and sandfly Sicilian (p=0.010) viruses. Raising domestic animals within the house was a risk factor for sandfly Sicilian (p=0.003) but not for sandfly Naples virus (p=0.148). All serum samples were negative for IgM antibodies against the tested viruses. Our study is the first documentation of West Nile and sandfly viruses in Jordan and calls attention to the possible health hazards of living close to wastewater treatment plants and their effluent channels.