New professional website

I created a new professional website at:

http://kmagori.weebly.com

One subpage of this website also allows you to follow the most recent news on my Twitter feed.

First West Nile cases of the year confirmed in New York City

The New York Department of Health and Mental Hygiene confirmed that two New Yorkers tested positive for West Nile. The two patients, a 73 year-old woman in Queens and a 60-year old man in Bronx became ill in late July and were hospitalized in early August with encephalitis and meningitis, respectively. Both patients are recovering, the woman still in the hospital, while the man has already been discharged. While the man had left New York City recently, and thus could have been infected elsewhere, the woman have not left the Big Apple in a long time. According to the NYC-DHMH, last year, there were 18 confirmed cases of West Nile, and three of these patients died. Citywide vector surveillance shows an increased percentage of West Nile-positive mosquito pools relative to last year's numbers. This year, WN-positive mosquito pools have been found in Brooklyn, Queens, Bronx and Staten Island, with most positive pools in Queens and Staten Island. Numbers can be found here. Accordingly, the NYC-DHMH is conducting larvicide [probably Bti] in parts of Staten Island, the Queens and the Bronx, as well as adulticide treatments in Brooklyn, Queens and Staten Island.

Imported case of chikungunya reported in Bologna, Italy

EmiliaNet and ProMedMail reports a confirmed imported case of chikungunya in a 50 year old Italian of Sri Lankan origin in Bologna, Italy. The imported case was detected following the patients visit to his doctor and his admission to Maggiore Hospital in Bologna with high fever, joint pains and widespread malaise. The symptoms started on August 1 2008, one day after his return from Sri Lanka. A chikungunya epidemic is raging on in Sri Lanka, with 10000-15000 cases reported in June in Ratnapura district alone. According to the reports the patients condition is stable, and he will be discharged during the day. Considering that the viraemic period of chikungunya is 2-6 days , I find it curious that he's not held in the hospital for isolation to prevent the dissemination of the disease.
Very prudently, a regional protocol was implemented to eliminate mosquito larvae (and hopefully adults) within a radius of 100 meters from the locations where the patient stayed between his arrival to Bologna and his hospitalization.

Hopefully, the swift and commendable reaction of the Italian authorities will be sufficient to avoid the recurrence of the chikungunya epidemic that occured in Emilio-Romagna last year. However, this case might be just the tip of the iceberg as many mildly symptomatic cases might not get reported. This coincides with the seasonal increase of the local Aedes albopictus population. This imported case  re-emphasizes the threat of chikungunya emergence in all areas with competent vector species and climatic conditions (e.g. the South-Eastern United States).

Human West Nile cases increasing in the US

Human West Nile cases are increasing according to ArboNet and ProMedMail (see figure). The total number of cases reported nearly doubled during the last week, and a similar trend is expected in the coming weeks. However, the total number of cases this year is significantly reduced compared to last year, and there were only two fatalities so far this year. At the same time, the Canadian Cooperative Wildlife Health Center reported 26 West Nile-positive birds in Ontario. Nebraska, Nevada and Ohio reported their first confirmed human West Nile cases this year in the last few weeks.

Three more cases of chikungunya found in Singapore

Three more cases of chikungunya have been found in Singapore, reports ProMedMail based on the People's Daily Online. The total number of chikungunya cases so far has been 48 in 2008.  The three new cases involve 2 foreign workers and a local delivery driver. Local transmission of the virus is assumed, as the patients have not left Singapore recently. The two foreign workers are treated in hospital, but the Singaporean driver was allowed to return to work.The Ministry of Health is carrying out active case detection in the location of these cases. The press release on the website of the Ministry of Health of Singapore also reveals that mosquito breeding sites have been found in the premises of 10 factories in the area, and the mosquito control has been initiated. The first case of chikungunya was reported in Singapore in January 2008. Mod TY on ProMedMail adds that the continuing chikungunya activity in Singapore, in spite of active efforts of breeding site reductions, represents a risk of introduction to countries which have significant populations of competent Aedes mosquitoes (such as the US), due to the significance of Singapore in terms of international trade and travel. Interestingly, the location of chikungunya cases mentioned in the report (Kranji Way) is quite close to the city of Johor Bahru in Malaysia. One would not be surprised to see additional chikungunya cases in that city.

Poll: Chikungunya in the South-Eastern United States

Do you think a chikungunya epidemic is credible threat in the South-Eastern United States?

On one hand, a competent vectors (Aedes albopictus) is present, climatic conditions are favorable, and international tourism offers plenty of opportunities for the importation of this disease. However, the human density is low compared to parts of the world where chikungunya epidemics occured, and the American lifestyle (driving cars, air-conditioning and window screens) limits the contact with vectors.

Please indicate your opinion using the online poll on the right. I will report back on its results.

First isolation of WNV in the Caribbean from sentinel chickens and mosquitoes

ProMedMail carries an interesting report on the first isolation of WNV from IgM seropositive sentinel chickens and mosquitoes in Puerto Rico (see the original paper in the American Journal of Tropical Medicine and Hygiene as well as in the Pan American Journal of Public Health). According to these sources, seroconversions started on June 4th 2007, peaked at 45% during June and July, and then fell steeply in August to 2%. However, seroconversions continued to occur at a low rate (2-6%) until October. Quite surprisingly, the article states that only 3 out of 4370 previously analyzed blood samples from dead birds, horses, pigs, monkeys and people were seropositive for IgG antibodies. Thus, sentinel chickens seem to be a highly valuable tool to detect the local activity of West Nile virus. ProMedMail also refers to an earlier review article in the Pan American Journal of Public Health on the spread of West Nile in Latin America. That paper invokes an interesting hypothesis for the apparent lack of human and equine cases of neuroinvasive West Nile in Latin America. They conjecture that a virulent strain of West Nile would be less likely to reach South America as it inhibits the reservoir bird to complete its difficult journey through the Caribbean. Apparently, a similar pattern is documented for St Louis Encephalitis virus where South American strains are less viremogenic than North American strains.

Latest update on West Nile situation in North America

In Canada, no human cases or seropositive dead birds were reported so far this year. However, in the US, according to CDC and ProMedMail,  5 states (Arizona, Mississippi, Oklahoma, Tennessee and Texas) reported a total of 8 West Nile cases in humans up to the 10th of June 2008. Six of these cases were classified as West Nile fever while 2 were neuroinvasive. Fortunately, no fatalities occurred so far. On ArboNet, the most recent case appears to be in May 2008 (21st epidemiological week) in Texas. Additionally, Alabama reported an equine infection (March 2008, 10th epidemiological week), while California and South Carolina reported WN-positive dead birds (the latest confirmed cases on the 22nd and 18th week, respectively). California and Florida reported WN seroconversion in sentinel animals (5th and 12th week, respectively). West Nile-positive mosquito pools have been reported from California (21st week), Illinois (23rd week), Indiana (23rd week), Louisiana (23rd week) and Texas (22nd week).Weeks given are the latest week for which West Nile positive pools have been found for that state.  Louisiana had a total of 251 positive mosquito pools reported up to 9th June 2008.

Yellow fever in Central African Republic

The WHO EPR Disease Outbreak News and ProMedMail reported 2 laboratory confirmed cases of yellow fever on the 15th May 2008 in Bozoum sub-prefecture, Ouham-Pende Prefecture of the Central African Republic. The Ministry of Health initiated an epidemiological investigation, and requested 64 931 doses of yellow fever vaccine from the Global Emergency Stockpile of Yellow Fever Vaccine, which is funded by the GAVI Alliance. The target population in the Bozoum sub-prefecture was estimated to be 55 035 people, which the Ministry of Health plans to vaccinate during a 3-day campaign starting on the 26th May. Mod. CP in the ProMedMail report notes that it would be important to know whether the 2 laboratory confirmed cases were isolated cases or potentially represent the start of an urban epidemic.

Hopefully the global emergency stockpile which was depleted in February following mass immunizations in South America have been adequately replenished to be able to provide supplies.

First case of West Nile fever in Texas in 2008

The first case of West Nile Fever in 2008 has been reported in Texas, Montgomery County, according to ProMedMail and the Houston Chronicle. The report states that although West Nile season typically starts in the summer, with mid-August through
mid-September being peak months because they're the hottest and driest months, it is not unusual to see cases as early as March and as late as December. However, one wonders how many cases of asymptomatic or mild West Nile infections must have been already gone unreported in the same area, given that 80% of infected people do not have any symptoms, and whether this early start signals an increased West Nile activity for Texas this year. Last year, Texas reported 170 neuroinvasive and 90 fever cases, and 17 deaths, according to state health records. The Centers for Disease Control and Prevention map of West Nile virus activity (as of 6 May 2008;  http://www.cdc.gov/ncidod/dvbid/westnile/Mapsactivity/surv&control08Maps.htm) as well as ArboNet shows that 2 human cases have been reported in Mississippi, one in Arizona, and one in Tennessee.

News focus on Aedes albopictus in current issue of Science

There is an excellent News Focus article on the global spread of Aedes albopictus  by Martin Enserink in the current issue of Science. The article gives the historical background of the spread of this mosquito, and highlights its potential public health consequences. Admirably, a clear distinction is made in regards to Aedes aegypti, the yellow fever mosquito. It's very interesting to see the differences in the judgment of different experts (notably Duane Gubler and Didier Fontanille) in terms of the level of risk attributed to Aedes albopictus. One aspect that I was lacking from this article was raising the possibility of a chikungunya outbreak in the South-Eastern United States. Nonetheless, this article is an excellent read and is highly recommended for anyone interested in mosquitoes and the diseases they spread.

Predictive study for Ross River Virus infections in the Darwin area of Australia published

Susan P Jacups of Charles Darwin University, Darwin, Australia publishes an elegant study in the upcoming issue of Tropical Medicine and International Health about predictive indicators for Ross River virus infection in the Darwin area of tropical North-Eastern Australia. Ross River virus is an Alphavirus, a close relative of chikungunya and Barmah Forest Virus, causing  similar symptoms of fever, joint pain and rash. The study is based on the statistical analysis of laboratory confirmed cases of RRV infection between 1991 and 2006 as well as climatic, tidal and mosquito data collected from 11 trap sites weekly in the study area. The authors identified the best predictors of RRV infections using three multivariate Poisson models. The best global model included rainfall, minimum temperature and the average monthly trap numbers of three implicated mosquito species populations (Culex annulirostris, Aedes vigilax, Aedes notoscriptus), and explained 63.5% of the deviance while predicting disease accurately. The model also indicated that predicted anthropogenic global climatic changes may increase RRV infections. My favourite point is that the predictors in the global model, since they all have a lag time of either 1 or 3 months, can be used as an early-warning system for potential RRV outbreaks. Such location-specific early-warning systems are badly needed for other vector-borne diseases, such as e.g. West Nile, dengue and chikungunya.

Dengue epidemic raging on in Rio de Janeiro

This years dengue epidemic is raging on in Rio de Janiero, with 76,385 cases reported in the city alone until 9th May this year, according to ProMedMail (see also here). In the whole state of Rio, 134,643 cases have been reported so far. In the state of Rio, 106 deaths occured due to dengue, with 3 additional cases between 4th and 10th May. 64 of these deaths occured in Rio de Janeiro.

At the same time, the governor of the state Rio Grande do Norte declared a state of emergency due to the 19,157 dengue cases, 78 DHF cases and 2 deaths reported until 3rd May this year in 154 cities in the state.

New issue of the American Journal of Tropical Medicine and Hygiene available

The 2008 May issue of the American Journal of Tropical Medicine and Hygiene is now available.

Particular papers of interest (to me) are:

Management of Travelers with Fever and Exanthema, Notably Dengue and Chikungunya Infections

Patrick Hochedez, Ana Canestri, Amélie Guihot, Ségolène Brichler, François Bricaire, AND Eric Caumes

Am J Trop Med Hyg 2008;78 710-713
http://www.ajtmh.org/cgi/content/abstract/78/5/710

Evaluation of Mosquito Densoviruses for Controlling Aedes aegypti (Diptera: Culicidae): Variation in Efficiency due to Virus Strain and Geographic Origin of Mosquitoes

Supanee Hirunkanokpun, Jonathan O. Carlson, AND Pattamaporn Kittayapong

Am J Trop Med Hyg 2008;78 784-790
http://www.ajtmh.org/cgi/content/abstract/78/5/784

Experimental West Nile Virus Infection in Jungle Crows (Corvus macrorhynchos)

Hiroaki Shirafuji, Katsushi Kanehira, Masanori Kubo, Tomoyuki Shibahara, AND Tsugihiko Kamio

Am J Trop Med Hyg 2008;78 838-842
http://www.ajtmh.org/cgi/content/abstract/78/5/838

Yellow fever in Peru and Ecuador

Two cases of sylvan yellow fever have been reported between 20-26 April 2008 in Peru, according to ProMedMail, based on the Epidemiological Bulletin of the Ministry of Health of Peru. The 1st case was a 23-year-old unvaccinated man from the Loreto department, while the 2nd case is a 21-year-old man of unknown vaccination status from Tocache Nuevo (Tocache district and province), San Martin department. He became ill between 6-12 Apr 2008. Since the beginning of 2008, there were 13 reported yellow fever cases in Peru, including 3 confirmed mortalities, 6 probable, and 4 discarded cases. Mod TY of ProMedMail asserts that from a public health point of view, it is fortunate that the reported sylvan yellow fever cases didn't spread into a major urban yellow fever outbreak.

Also, the CDC updated its yellow fever risk map for Ecaudor, following the recommendation of the Ecaudor Ministry of Health of yellow fever vaccination for all travelers to the following provinces in the Amazon Basin: Morona-Santiago, Napo, Orellana, Pastaza,
Sucumbios, and Zamora-Chinchipe.  This is in addition to the current recommendation for yellow fever vaccination for travelers going to areas along the eastern slopes and to the east of the Andes Mountains. At present, yellow fever vaccination is only required for travelers entering Ecuador if they are greater than one year of age and if they are coming from a country in the yellow fever endemic zone.

Breaking news: Chikungunya back in Kerala

ProMedMail reports based on the Thaindian News, that 6 cases of chikungunya have been confirmed in Vatakara and 9 cases confirmed in Maruthonkara, both in Kozhikode district, in the northern part of Kerala state, India. The outbreak was reported Tuesday (04/08/2008), following heavy and untimely rains. The index case appear to be a person who travelled from Tamil Nadu [Is there an outbreak as well in Tamil Nadu? No report on that available.] A high density of Aedes aegypti mosquitoes was noted at the location of the outbreak, and a campaing to reduce the mosquito density has been initiated. According to the report, Kozhikode district, specifically the town of Kodenchery reported a large number of cases last year.

According to another report in the same journal, Poonam Khetrapal Singh, the deputy regional director of WHO SEARO (South-East Asian Region), the chikungunya outbreaks in Kerala in the last two years is directly attributable to climate change. The report claims that 100 fatalities and more than 100,000 [or rather 1,000,000] chikungunya cases occured in Kerala state. Kerala State put together an action plan to control disease, with each district allocated 500,000 Rs for prevention.

These news are very disconcerting as last year the first cases in Kerala have been reported more than a month later than this year. Unless vector control campaigns are much more successful than previously, another huge outbreak of chikungunya in the region is expected this year. This will also enable the importation of chikungunya to Europe and the US, where transmission by local Aedes albopictus is a real possibility.

Click here to see the location of these outbreaks.

More information on the dengue outbreak in Rio de Janiero

During the weekend, CNN ran two additional articles on the dengue outbreak in Rio de Janiero containing some additional information. According to the first report, 2000 soldiers and firefighters joined the fight against dengue, some of them going door-to-door to educate the public about source-reduction. Additional to the 67 fatalities already reported, 58 suspected deaths are also investigated. An average of 1.4 cases of dengue are reported per minute (that's 2016 cases per day). 400 patients are admitted to one of the field hospitals, of which 65% have dengue. The reported fatalities are also broken down with 21 due to DHF, 14 due to DSS, while 32 due to the 'more common form of the disease' [possibly these cases do not satisfy all the requirements of the WHO DHF/DSS classification]. According to an article in the newspaper O Globo and ProMedMail, the public health infrastructure in Rio de Janeiro has collapsed under the pressure of the dengue outbreak, amplified by an influx of patients from the countryside. CNN also reports of the difficulty in vector control in Caxias neighborhood of Rio, which is ruled by drug dealers who don't let authorities and outsiders into their territory. Residents are feeling neglected and probably in need of basic public health services.

Dengue situation worsening in Rio de Janiero

CNN carries today a tragic report on the worsening dengue situation in Rio de Janeiro, Brazil. According to the report, the number of dengue fever cases this year has reached 57,010 , while the number of DHF cases exceeded 513. There were 67 deaths connected to dengue so far, with more than half of those in children below the age of 13. Judged by the report, the public health infrastructure is clearly overwhelmed, with patients transported to 3 military field hospitals near the city (see shocking images at the same CNN report). Authorities are considering to invite assistance from Cuba, where physicians are very experienced at treating dengue. Average hospital waits range from 8 to 28 hrs at different hospitals in the city. Earlier this week, the government also asked other Brazilian states to send hundreds of their physicians to help save the population in Rio. The Brazilian army is also contributing to the efforts. I would encourage any reader of the blog from the region to submit their firsthand reports.

New issue of the American Journal of Tropical Medicine and Hygiene published

A new issue of the American Journal of Tropical Medicine and Hygiene has been published. I wish UGA would have a subscription for it such that I could access the articles as they come out. It has a number of interesting articles, but I 'd just like to highlight a few here:

Ephantus J. Muturi, Peter Burgess, AND Robert J. Novak

Malaria Vector Management: Where Have We Come From and Where Are We Headed?
Am J Trop Med Hyg 2008 78: 536-537. [Full Text] [PDF] 

          Anna M. Winters, Bethany G. Bolling, Barry J. Beaty, Carol D. Blair, Rebecca J. Eisen, Andrew M. Meyer, W. John Pape, hester     G. Moore, AND Lars Eisen Combining Mosquito Vector and Human Disease Data for Improved Assessment of Spatial West Nile Virus Disease Risk
          Am J Trop Med Hyg 2008 78: 654-665. [Abstract] [Full Text] [PDF] 

Roberto Barrera, Elizabeth Hunsperger, Jorge L. Muñoz-Jordán, Manuel Amador, Annette Diaz, Joshua Smith, Kovi Bessoff, Manuela Beltran, Edgardo Vergne, Mark Verduin, Amy Lambert, AND Wellington Sun First Isolation of West Nile Virus in the Caribbean
Am J Trop Med Hyg 2008 78: 666-668.

[Abstract] [Full Text] [PDF] 

William K. Reisen, Ying Fang, AND Aaron C. Brault Limited Interdecadal Variation in Mosquito (Diptera: Culicidae) and Avian Host Competence for Western Equine Encephalomyelitis Virus (Togaviridae: Alphavirus)
Am J Trop Med Hyg 2008 78: 681-686.

[Abstract] [Full Text] [PDF] 

Christopher D. Paddock, Susana Fernandez, Gustavo A. Echenique, John W. Sumner, Will K. Reeves, Sherif R. Zaki, AND Carlos E. Remondegui Rocky Mountain Spotted Fever in Argentina
Am J Trop Med Hyg 2008 78: 687-692.

[Abstract] [Full Text] [PDF] 

Fungi vs insects 1:0

In a recent paper in Heredity, Alex Kraaijeveld and Charles Godfray show that Drosophila melanogaster has little chance in developing resistance to fungal pathogens such as Beauveria bassiana. This is significant as the same fungi and the related Metarhizium anisopliae are targeted to be used as biopesticides against disease vectoring mosquitoes (such as Anopheles) and other insect pests. In this paper, in a long-term artificial selection experiment for 15 generations, selected flies did not have higher overall fitness after infection compared with control lines. However, late-life fecundity increased in the selected lines, which may indicate evolved tolerance of the fungal pathogen. Nonetheless, this increase was balanced by decreased early-life fecundity in the selected lines. More importantly, in the absence of fungal infection, selected lines had lower overall fitness than control flies. In general, the paper demonstrated that Drosophila have a weak selection response to the fungal infection. If this is true to insects in general and to mosquitoes in particular, this might suggest that resistance to such fungal pesticides will not evolve easily and rapidly. This might give  us just another novel tool for vector control, which is badly needed to reduce vector-borne diseases globally.