Detection of Orientia tsutsugamushi, the causative agent of scrub typhus, in a novel mite species, Eushoengastia koreaensis, in Korea

To identify potential vector species of scrub typhus in the Republic of Korea (ROK), chigger mites were harvested from wild rodents captured at nine localities in October 2005. The bodies of the chigger mites were individually punctured with a fine pin, squeezed out internal contents, and examined for Orientia tsutsugamushi DNA by nested polymerase chain reaction. The exoskeleton of associated chiggers was mounted on glass slides with polyvinylalcohol (PVA) medium for identification. Among 830 individuals belonging to 4 genera and 14 species, O. tsutsugamushi was detected from 22 chiggers of six species, with an overall infection rate of 2.7%. The infection rate was highest for Leptotrombidium palpale (5.3%), followed by Neotrombicula japonica (4.3%), Leptotrombidium scutellare (3.7%), Leptotrombidium orientale (3.6%), Eushoengastia koreaensis (1.9%), and Leptotrombidium pallidum (1.5%). This study first reported O. tsutsugamushi infection from N. japonica and E. koreaensis larvae in the ROK. The population densities of L. pallidum (33.4 chiggers/rodent), historically confirmed as a primary vector of scrub typhus in the ROK, were high, whereas its infection rate was relatively low (1.5%). However, E. koreaensis was only collected from 154 individuals at seven collection sites and its infection rate was demonstrated relatively high (mean 1.9%). Additional studies are needed to determine the role of vector species in the epidemiology of scrub typhus.     

The legitimacy of rattlesnake bites in central Arizona

Previous authors have classified poisonous snake bites as being legitimate or illegitimate, depending on whether the victim was taking unnecessary risks with a snake before being bitten. We reviewed medical records of 86 consecutive rattlesnake bite victims cared for at a single medical center to determine legitimacy of snake bites. A bite was considered illegitimate if, before being bitten, the victim recognized an encounter with a snake but did not attempt to move away from the snake. A legitimate bite was said to have occurred if a person was bitten before an encounter with a snake was recognized or was bitten while attempting to move away from a snake. The study group was made up of 75 male (87.2%) and 11 female (12.8%) victims. Seventy-four percent were 18 to 50 years old, and 15% had been bitten previously. Only 43.4% of all bites were considered legitimate, and pet (captive) snakes accounted for almost one third of all illegitimate bites. The ingestion of alcoholic beverages was associated with 56.5% of illegitimate bites versus 16.7% of legitimate bites (P less than .001). While 74.4% of bites were to upper extremities, only 27% of upper extremity bites were legitimate. All bites to the lower extremity were legitimate (P less than .001). Of 14 individuals bitten by pet snakes, all were men and 64.3% were under the influence of alcohol at the time of the bite.(ABSTRACT TRUNCATED AT 250 WORDS)     

Septic shock secondary to scrub typhus: characteristics and complications

Scrub typhus is an acute febrile illness caused by infection with Orientia tsutsugamushi transmitted by the bite of larval trombiculid mites (chiggers). A prospective study was conducted in septic shock patients in Maharat Hospital, Nakhon Ratchasima Province, Thailand, from 12 November 2001 to 5 January 2002. Of the 51 septic shock patients studied during the 7 week period, 18 (35.3%) were found to have evidence of scrub typhus infection; 3 patients (16.7%) died. In this study, septic shock caused by Orientia tsutsugamushi is the most prominent (35.3%) in endemic area of scrub typhus. Scrub typhus with septic shock patients results in organ failure: respiratory failure, DIC were predominant, followed by renal and hepatic involvement. Two deaths were due to respiratory failure and one death was as a result of combined respiratory and renal failure. Fever was the most common symptom, followed by headache, myalgia and dyspnea; lymphadenophathy and eschar are common signs. Laboratory findings revealed that almost all of the patients had a mild leukocytosis, reduced hematocrit and thrombocytopenia; SGOT, ALP, direct bilirubin (DB), total billirubin (TB), BUN, Cr were elevated; hypoalbuminemia was noted. Urinalysis showed that 88.9% of the patients had albuminuria. 77.8% of patients had abnormal chest X-rays.     

Spatial analysis of scrub typhus infection and its association with environmental and socioeconomic factors in Taiwan

We analyzed the spatial distribution of human cases of scrub typhus on the main island of Taiwan from 2003 to 2008 and implemented an island-wide survey of scrub typhus vectors (trombiculid chiggers) in 2007 and 2008. The standardized incidence rate 'SIR' incorporating inter-district variations in population, gender and age was correlated with environmental and socioeconomic variables. Higher incidence and SIR rates were clustered in the less developed, mountainous regions of central and eastern Taiwan. Higher SIRs were also associated with a higher proportion of dry-field farmers in the population, a higher normalized difference vegetation index (NDVI) and lower mean annual temperature, but was not associated with rainfall. Small mammal hosts in high-SIR districts harbored more chiggers and had higher rates of seropositivity against Orientia tsutsugamushi Hyashi, the etiologic agent of scrub typhus, compared to low-SIR districts. The concurrence of a higher proportion of dry-field farmers and higher NDVI has likely led to the clustering of scrub typhus in the mountainous regions of Taiwan. Further individual-level study of the risk factors associated with scrub typhus, and a better understanding of the effect of environmental factors on chigger abundance, should help to prevent scrub typhus in Taiwan.     

A new member of the trombiculid mite family Neotrombicula nagayoi (Acari: Trombiculidae) induces human dermatitis

We present the first definitive evidence that the mite Neotrombicula nagayoi bites humans under natural conditions in Japan. Initially, bites resulted in mild pruritus without pain. However, skin reactions increased gradually year by year with severe pruritus with pain being reported by the victim after being bitten repeatedly. Six species of trombiculid mites comprising three genera were isolated from soil samples collected from August to October in both 2001 and 2002 at a study site where a man was bitten by N. nagayoi. The dominant species was L. intermedium (72.4%) followed by L. pallidum (8.3%) and N. nagayoi (8.1%). N. nagayoi was found only in August and September. We did not detect the pathogen Orientia tsutsugamushi in any of the unfed larvae, including N. nagayoi, collected from the soil samples.     

Numbers of Leptotrombidium (Leptotrombidium) deliense (Acarina: trombiculidae) and prevalence of Rickettsia tsutsugamushi in adjacent habitats of peninsular Malaysia.

Numbers of L. (L.) deliense larvae were determined in adjacent habitats over a 16 month period. Both R. argentiventer and R. tiomanicus were highly efficient hosts for L. (L.) deliense. R. argentiventer was host to significantly greater numbers of chiggers per rat than was R. tiomanicus. The 2 habitats were similar in numbers of chiggers collected. No consistent correlation was apparent between numbers of chiggers and any single weather factor, but the chigger population seemed to be adversely affected by a 2 month period during which total evaporation greatly exceeded total rainfall. Direct fluorescent antibody examination of tissues from unfed L. (L.) deliense showed that 2 of 420 larvae (0.5%) contained organisms morphologically resembling R. tsutsugamushi. Considering the vector load and numbers of chiggers being returned to the ground by a given host, a rate of 0.5% appeared adequate to account for the prevalence rate of R. tsutsugamushi observed in the 2 host species.     

Rickettsial diseases in travelers

Often undiagnosed in travelers with acute nonspecific febrile illness, gastrointestinal, abdominal, pulmonary, neurologic, or cutaneous signs and symptoms, rickettsial diseases are transmitted in particular geographic and ecologic settings by ticks, fleas, chiggers, and lice. Recognition of an eschar at the vector inoculation site can be a key diagnostic clue for scrub typhus, African tick bite fever, and other tick-borne spotted fevers. Although laboratory confirmation is necessary, usually during convalescence, for an accurate diagnosis, a clinical diagnosis and empiric treatment with doxycycline are the standard practical approach. Knowledge of potential exposure, the natural history of the infection, and incubation periods of each rickettsiosis assist in considering particular rickettsioses.     

Detection of rickettsioses and Q fever in Sri Lanka

Current serological evidence suggests the presence of scrub typhus and spotted fever group (SFG) rickettsiosis in Sri Lanka. Our objective was to identify rickettsial agents/Q fever as aetiological causes for patients who were presumed having rickettsioses by the presence of an eschar or a rash. Sera from patients with unknown origin fever from Matara were tested by immunofluorescence for SFG rickettsial antigens, typhus group rickettsiae, Orientia tsutsugamushi, and Coxiella burnetii antigens. Thirteen (7.3%) of the patients presented with a rash, 11 (6.1%) had an inoculation eschar, and 16 patients recalled a tick or flea bite. We found that 25 (14%) patients had scrub typhus, 6 (3%) SFG rickettsioses, 3 (1.6%) acute Q fever, 3 (1.6%) murine typhus, and 3 (1.6%) were infected by Rickettsia felis. In addition to already described scrub and murine typhus, we found that R. felis and C. burnetii infections should be considered in Sri Lanka.     

Epidemiological studies on host animals of scrub typhus of the autumn-winter type in Shandong Province, China

In order to elucidate the host animals of scrub typhus in Shandong Province, epidemiological studies on host rodents of the autumn-winter type scrub typhus were carried out from 1995 to 2002 at four localities in the Shandong Province. Based upon ecological observations of the composition, seasonal fluctuation of animal hosts, isolation of Orientia tsutsugamushi, detection and identification of serotypes of antibodies to O. tsutsugamushi were conducted. Two thousand eight hundred and eighty-four rodents and insectivores were captured, including 2,055 Apodemus agrarius (71.26%), 408 Cricetulus triton (14.15%), 64 C. barabensis (2.22%), 12 Crocidura suaveolens (0.42%), 313 Rattus (R.) norvegicus (10.85%), 32 Mus (M.) musculus (1.11%). A. agrarius was predominant in the field and the seasonal fluctuation was correlated significantly to that of scrub typhus (r=0.810, p<0.005). R. norvegicus was predominant indoors. The average capture rate per year in the field was 12.76% from 1995 to 1997. Of the total 2,884 rodents and insectivores captured out- and in-doors, 527 were living rodents (including 335 A. agrarius, 119 C. triton, 6 C. barabensis, 2 C. suaveolens, 63 R. norvegicus and 2 M. musculus, and 15,467 chigger mites were collected from them. Two hundred and fifty-three of 335 A. agrarius were parasitized by chiggers, showing 75.52% (253/335) of the infestation rate and 17.53 of the chigger index; 106 C. triton were parasitized by chiggers, showing 89.08% (106/119) infestation rate and 75.93 of the chigger index. The average antibody positive rate of rodents was 14.78%. The seasonal change of the antibody positive rate was higher during December-February (the second year), and varied from 20% to 28%, but the level of antibodies remained relatively low (5.26-16.67%) during March-November. The results of serotyping with 47 antibody-positive sera were as followings: 39 sera were Gilliam types, 7 sera were Karp types, 1 serum was Kato type. Twelve strains of O. tsutsugamushi were isolated from A. agrarius (8 strains), C. triton (3 strains) and R. norvegicus (1 strain), out of the isolated 12 strains, 10 were Gilliam strains, 2 were Karp strains. A. agrarius and R. norvegicus were the main host animals in out- and indoors respectively.     

Distinctive epidemiologic and clinical features of common krait (Bungarus caeruleus) bites in Sri Lanka

A prospective study was designed to define epidemiologic and clinical features of krait bites to improve diagnosis, management, and prevention. Among 762 cases of venomous snake bites admitted to 10 Sri Lankan hospitals in which the snake responsible was brought and identified, 88 (11.5%) were caused by common kraits (Bungarus caeruleus). Bites were: most frequent in September through November. Distinctive features of B. caeruleus bites (compared with bites by other species in parentheses) were bitten while sleeping on the ground, 100% (1%); indoors, 100% (49%); between 2300 and 0500 hours, 100% (3%). Only 13% of krait victims were bitten on their lower limbs (82%), only 9% had local swelling (in all cases mild) at the site of the bite (93%), 64% developed respiratory paralysis (2%), and 91% experienced (often severe) abdominal pain (10%). Case fatality was 6% (3%). This distinctive pattern of epidemiology and symptoms will aid clinical recognition (syndromic diagnosis) and prevention of krait bite envenoming.     

Severe Japanese spotted fever successfully treated with fluoroquinolone

A 77 years old woman who had a bite with eschar on her left arm, was admitted to emergency ward in our hospital, because of high fever, severe malaise, skin eruption, and consciousness disturbance beginning 5 days previously. She was diagnosed as Japanese spotted fever by seropositive of Rickettsia japonica (R. japonica) antibody, and successfully treated with fluoroquinolone, after minocycline hydrochloride had been proven ineffective. R. japonica-specific DNA was detected by PCR from the tick: Haemaphysalis hystricis larvae collected from a mountainous location in Fukuoka, Japan where the patient had been bitten.     

Epidemiology of sea-snake bites.

Epidemiological features as reflected by 101 patients with unequivocal sea-snake bite received in north-west Malaya are reviewed. Enhydrina schistosa caused over half the bites, including seven of the eight fatal bites. It is the most dangerous sea-snake to man. Over 90 per cent of the victims were male and 80 of the 101 patients were fishermen bitten at their job. Most victims were bitten on the lower limb through treading on the snake, and this resulted in more cases of serious poisoning than upper limb bites (caused through handling nets, sorting fish and so on). Only 14 cathers were bitten (through treading on the sea-snake; no bathers were bitten while swimming). In patients coming to hospital more than six hours after the bite, there was a four-fold increase in serious poisoning compared with patients coming within six hours of the bite. Thus, as time elapses after the bite, the victim is less likely to seek medical help unless poisoning is severe. Despite the lethal toxicity of sea-snake venom, in patients seen during 1957-61 before sea-snake antivenom became available, the mortality was only 10 per cent. Trivial or no poisoning followed in 80 per cent of the bites. On the other hand, of 11 patients (20 per cent) with serious poisoning, over half (six patients) died despite supportive hospital treatment. These epidemiological features observed in Malaya probably apply to most fishing folk along Asian coastlines where sea-snakes abound. If this is so, sea-snake bite must be a common hazard feared by millions of fishing folk, and a common cause of illness and death. But it is unlikely that the extent of this problem will be revealed to orthodox medicine for many decades because most fishing villages are far from medical centres; and even if hospitals or medical centres are available, fishing folk are usually reluctant to attend them. Only one species of sea-snake, Pelamis platurus, extends to the east coasts of Africa and west coasts of the tropical Americas, but for various reasons this species does not appear to constitute much of a hazard to fishing folk in these areas. Although bathers are occasionally bitten along Asian coasts, when they inadvertently tread on a sea-snake, the risk of sea-snake bite in this area is extremely low. The prevention of sea-snake bite and poisoning is considered. Highly effective antivenom is now available for treating victims with serious poisoning; death should not occur provided adequate medical treatment is given within a few hours of the bite. The main problem is provision of adequate medical care at rural medical centres and overcoming the reluctance fishing folk often have in attending these centres.     

福建近年恙螨感染恙虫病东方体的检测研究

目的　检测恙螨幼虫体内恙虫病东方体, 分析福建恙虫病可能流行的趋势。方法　从福建山区及沿海地区捕鼠采集恙螨幼虫, 通过分类鉴定, 以每只鼠体的寄生螨作为一个被检单位, 用套式 Ｐ Ｃ Ｒ 扩增恙虫病东方体 Ｓｔａ ５８ｋ Ｄａ 基因的８８ｂｐ 片段, 以确定恙螨幼虫是否携带本病原, 继而估计该地区是否存在恙虫病疫源地。结果　从１０５ 份被检单位的恙螨幼虫检出７ 份恙虫病东方体阳性标本, 主要宿主为黄毛鼠, 主要媒介为纤恙螨属的地里纤及小板纤恙螨, 与有关资料比较,证实本省恙虫病的宿主和媒介未发生明显变化。结论　福建沿海地区恙螨的恙虫病东方体的感染率高于山区, 疫源地有继续扩大的趋势。     

Post exposure management of animal bite cases attending a primary health center of Delhi

Rabies is an ancient disease of mankind. Every year 4 million people are exposed worldwide after animal bite and around 60000 fell victim to the rabies of which more than 95% of cases are bitten by the dogs. Rabies is a disease associated with many myths. The present study was conducted to find out the clinical profile of the animal bite cases including the common practices, precautions adopted by them after animal bite and lastly the extent and completion of post exposure treatment. Total 147 cases of animal bites attended the OPD during the study. In present study, 123 (83.7%) cases were bitten by dogs, followed by monkey (8.2%) and cat (8.2%). Majority (54.4%) suffered class II bites followed by class I (31.3%) and class III bite (14.3%). Of the total 147 cases, 116 cases (78.9%) completed post exposure prophylaxis which was observed higher among male and in younger age group.     

DNA profiling of human blood in anophelines from lowland and highland sites in western Kenya

We used polymerase chain reaction (PCR)-based DNA profiling to determine the person from whom Anopheles funestus and An. gambiae collected in natural human habitations obtained their blood meals. Less than 20% of human hosts contributed to > 50% of all blood meals, and 42% were not bitten at all, including people in the age group bitten most often. As expected, bites were unevenly distributed by age (young adults > older adults > children). Use of untreated bed nets by adults, but not children, seemed to redirect bites to children. Multiple blood meals in a single gonotrophic cycle occurred frequently enough to be epidemiologically important (14% for An. funestus and 11% for An. gambiae). Mosquitoes that did not bite a person who slept in the collection house can affect estimation of entomological risk. Mosquito-human interactions did not differ across ecologically and epidemiologically distinct highland and lowland sites.     

Copperhead snakebites: clinical severity of local effects.

STUDY OBJECTIVE: We sought to evaluate the type and extent of local reactions after copperhead snakebites. METHODS: We performed a retrospective evaluation of copperhead snakebites in West Virginia between January 1, 1995, and September 30, 1999. A local effect scoring system was used to define a clinically significant local reaction. A bite was considered clinically significant if the bitten individual's average local effect score was 3 to 4 (range, 0 to 4). RESULTS: Ninety-two patients met the inclusion criteria; an average local effect score of 3 to 4 was documented in 33% (n=30). The foot was the most common bite location (46% of all bites); 87.5% of bites to the finger (n=8) resulted in a score of 3 to 4. Eight (36%) of 22 patients who presented to the emergency department within 2 hours of a bite and whose highest local effect score was 3 to 4 did not have their highest score until greater than 4 hours after the bite. The average length of stay (score 3 to 4) was 3.4 days compared with 1.1 days for those with a score of 3 or less. CONCLUSION: Clinically significant local effects (eg, pain requiring parenteral analgesics, ecchymosis, swelling of over one half of the bitten extremity) occurred in one third of patients in our study. The generalization of copperhead snakebites as mild or of benign clinical significance should be reconsidered.     

The location of the infecting tick bite and the severity of the course of tick-borne encephalitis

Analysis of 846 epidemiological charts of unvaccinated tick-borne encephalitis patients in the period of 1956-1985 established that in 21% cases the disease resulted from multiple bites of the ticks, in 67.3% it occurred from single bites. In 11.7% of the patients, the bite was denied. Single infecting bites were mostly those of the head and neck (39.2% cases), especially frequent among children (84.9%). The upper part of the body and hands were bitten less frequently (16.7 and 12.5%, respectively). Other sites of the bite were reported in 6-10%. The most complicated pattern of tick-borne encephalitis is observed in case of multiple bites: two-fold increase in mortality rates compared to single bites (23.2 vs. 10.7%) and higher percent of focal forms (72.7 vs. 56.5%). In case of the single bites a certain correlation is observed between the site of the bite and the outcome of the disease: fatal outcomes are most frequent in case of the bites in the axilla, arms (14-16%), head and neck (11.2%), and less frequent in case of the bites in the lower limbs (5.9%) and groin (0). The nature of the infecting bite determines, to a great extent, the pathogenesis and outcome of the disease. The prevention of multiple bites would help considerably to reduce mortality rates.     

Management of poisonous snake bites in southern Taiwan

Snake bite envenomation is not uncommon in Taiwan. This study focuses on the pattern of poisonous snake bites and their management in southern Taiwan over a 5-year period. The case histories of 37 patients with poisonous snake bites admitted to the Kaohsiung Medical University Hospital between June 2001 and July 2005 were analyzed retrospectively. Three patients, bitten by unknown species of venomous snakes, were excluded from this study. The frequency of snakebites from each species of snake, the local and systemic manifestations of snake bite, treatment of complications and final outcomes were analyzed. Of the remaining 34 patients, 11 (32.4%) were bitten by bamboo vipers, 10 (29.4%) by Russell's pit vipers, 8 (23.5%) by Taiwan cobras and 5 (14.7%) by Taiwan Habu. The majority of snake bites (28) occurred between May and November. Those affected were mainly outdoor hikers (14) and workers (9). The antivenin requirements for treatment in the emergency room were in accordance with standard procedures. No mortality was noted among those envenomed by poisonous snakes. Although poisonous snake bite is not a common life-threatening emergency in the study area, we observed both an environmental risk and a seasonal incidence of snake bite. Keeping the varied clinical manifestations of snake bite in mind is important for effective management. Ready availability and appropriate use of antivenin, close monitoring of patients, institution of ventilatory support and early referral to a larger hospital when required, all help reduce mortality.     

云南省小型哺乳动物寄生恙螨群落研究

目的探讨云南省恙螨的群落结构及生物多样性特征。方法选取云南省16个县（市）为调查点，现场用鼠笼加食饵诱捕小型哺乳动物（小兽），收集耳廓和外耳道全部恙螨，常规分类、鉴定。恙螨的群落结构与生物多样性特征分别用香浓-威纳（Shannon-Wiener）指数（多样性和均匀性指数）、辛普森（Simpson）多样性指数、丰富性指数和优势指数分析。结果捕获小兽6888只，属5目10科26属，在双耳部检获恙螨共87416只，属3亚科21属192种，存在9种优势恙螨。宿主动物寄生恙螨的多样性与丰富性指数依次为啮齿目〉食虫目〉攀驹目。各生境群落中，丰富性指数与多样性指数山区森林灌丛〉山区耕地室内〉坝区草甸耕地〉坝区室内房周。优势指数均较低。9种优势恙螨种类的生态位宽度依次为寒冬纤恙螨0．81，乡野纤恙螨0．57，小板纤恙螨0．52，绒鼠纤恙螨0．51，中华纤恙螨0．42，西盟合轮恙螨0，39，枪棒爬虫恙螨0．39，树驹纤恙螨0．27，副须纤恙螨0．04，其中任意两螨种间的生态位重叠指数在0～0．54间。群落内主要恙螨种类的空间分布呈聚集型。结论云南省恙螨群落结构复杂，物种多样性较高，群落内主要恙螨种类呈聚集型分布，优势恙螨的生态位宽度与生态位重叠差异均明显。