An ecological and epidemiological single-season survey of Anaplasma and Ehrlichia positive ticks in Victoria Falls National Park, Zimbabwe.

There is an urgent need for continued research on the ecology of tick-borne diseases in Africa. Our objective was to provide a preliminary description of the ecology and epidemiology of tick species, tick-borne pathogens, and animal hosts in Zimbabwe, focusing efforts at Victoria Falls National Park, for a single season. We tested the hypothesis that tick surveillance and pathogen screening data can be used to model associations among ticks, hosts, and pathogens. We collected ticks from domesticated animals and wildlife in Zimbabwe and screened the ticks for the presence of Anaplasma and Ehrlichia bacteria. Nearly 30% of the screened ticks were PCR-positive; 89% of tick species were PCR-positive, and 88% of animal species carried at least one PCR-positive tick. We sequenced a subset of amplicons that were similar to three Anaplasma species and three Ehrlichia species. The odds of a tick being PCR-positive increased when many ticks were collected from the host or the tick was collected from a cow (domesticated animal). Tick species shared host species more often than expected. We demonstrate that ticks in northwestern Zimbabwe present a One Health problem for nearby wildlife and humans.

Supplemental feeding of deer reduces tick abundance in Mississippi, U.S.A.

Prior research on baiting and feeding of wildlife found changes in habitat and the concentration of wildlife on a local scale (e.g., hundreds of meters). Since changes in habitat and host density affect ticks, feeding wildlife may lead to changes in tick and tick-borne disease ecology. We quantified the effect of feeding deer on ticks and tick-borne diseases at 79 pairs of sites with and without deer feeders during May-August of 2019 and 2020. We captured 0.4 fewer adult (p<0.05) and 1.2 fewer nymphal ticks (p=0.01) at feeder sites. This effect intensified over time with one fewer tick trapped at old feeders (≥5 years) compared to new feeders (<5 years, p<0.05). Greater daily wildlife visitation rates (p<0.001) may have allowed questing ticks to encounter hosts more readily. Most collected ticks were Amblyomma americanum (92.8%), a vector of Ehrlichia and Rickettsia pathogens, though prevalence of these pathogens did not differ (p>0.13) at a local scale. Supplemental deer feeding appears to influence ticks, possibly due to decreased tick habitat and increased wildlife use around feeders. Our findings indicate feeding does not lead to increased prevalence of Ehrlichia or Rickettsia bacteria within A. americanum locally.

The Common Bed Bug (Hemiptera: Cimicidae) Does Not Commonly Use Canines and Felines as a Host in Low-Income, High-Rise Apartments.

The common bed bug (Cimex lectularius L.) is a known pest and an obligate blood-feeding ectoparasite. Bed bugs can feed on warm-blooded animals including humans, bats, poultry, and rabbits, but no research has investigated the use of companion animals (canines and/or felines) as a blood source. This study investigates how long known host DNA could be detected in a bed bug and the prevalence of bed bugs feeding on companion animals. Laboratory-reared bed bugs were fed host blood to determine how long DNA of human, feline, canine, and rabbit blood could be detected up to 21 d postfeeding. Additionally, 228 bed bugs were collected from 12 apartments with pets (6: canine, 5: feline, and 1: canine and feline), characterized as engorged or unengorged, and then screened with host-specific primers to identify the bloodmeal. Host meals of human, rabbit, feline, and canine blood were detected up to 21 d after feeding laboratory strains. All bed bugs died after feeding on the canine blood, but DNA could be detected up to 21 d post feeding/death. Of the field-collected bed bugs analyzed, human DNA was amplified in 158 (69.3%) bed bugs, canine DNA amplified in 7 bed bugs (3.1%), and feline DNA amplified in 1 bed bug (0.4%). Results of this study suggest that bed bugs predominately feed on humans and rarely feed on companion animals when they cohabitate in low-income, high-rise apartments. Additionally, results from this study warrant future investigations into host use by bed bugs in different housing structures and socioeconomic environments.

Spray and Pour-On Acaricides Killed Tennessee (United States) Field-Collected Haemaphysalis longicornis Nymphs (Acari: Ixodidae) in Laboratory Bioassays.

Haemaphysalis longicornis Neumann (Asian longhorned tick) is an exotic and invasive tick species presenting a health and economic threat to the United States (U.S.) cattle industry due to its ability to transmit pathogens and infest hosts in large numbers. The objective of this study was to evaluate available products at causing H. longicornis mortality in a laboratory bioassay. The efficacy of products was evaluated at label rates using H. longicornis nymphs collected from a cattle farm in eastern Tennessee in two different bioassays (spray or dip) against untreated controls. After exposure, ticks were transferred to clean petri dishes and checked for mortality at 0, 1, 2, 3, 4, 21, 24, and 48 h post exposure. No mortality occurred in the untreated controls, whereas all treated ticks were dead within 24 h of exposure (P < 0.0001). These findings support the hypothesis that currently available spray and pour-on products are effective at causing H. longicornis mortality. We conclude that these acaricides can be used as a component to prevent H. longicornis dispersal and for control in the U.S.

Paradoxical increase in rate of catabolism of low-density lipoproteins after hepatectomy.

It has been suggested that the liver may be a major site for irreversible degradation of low-density lipoprotein (LDL). The disappearance of autologous (125)I-labeled LDL from plasma was compared in intact and in hepatectomized swine. Contrary to expectations, the rate of irreversible removal of LDL from plasma was increased rather then decreased by hepatectomy. These studies suggest that the liver is not a major site for LDL removal. We propose further that the liver (or some function requiring an intact liver) may affect the metabolism of LDL in a manner that prolongs its lifetime in the plasma compartment.

Bed Bug (Hemiptera: Cimicidae) Detection in Low-Income, High-Rise Apartments Using Four or Fewer Passive Monitors.

Bed bug, Cimex lectularius L., management in low-income, high-rise housing for the elderly and disabled can be difficult. Early detection is key to slowing their spread, and reducing management cost and time needed for control. To determine the minimum number of passive monitors needed to detect low-level bed bug infestations in this environment, we evaluated three monitors placed one, two, or four per apartment in a 3 by 3 experimental design. One sticky monitor, The Bedbug Detection System, and the two pitfall monitors, ClimbUp Insect Interceptors BG and BlackOut BedBug Detectors, were evaluated. Bed bugs were trapped by the ClimbUp Insect Interceptors BG and the BlackOut BedBug Detector in 88% and 79% of apartments, respectively, but only in 39% of the apartments monitored with The Bedbug Detection System. The Bedbug Detection System required significantly longer time to detect bed bugs than either the ClimbUp Insect Interceptor BG or the BlackOut BedBug Detector. With the less effective Bedbug Detection System data removed from analyses, detection rates ranged from 80 to 90%, with no significant differences among one, two, or four monitors per apartment. Results indicate it is especially important to include a bed placement when only placing a few monitors. Future work should compare the combination of cursory visual inspections with various monitor numbers and placements per apartment to determine the most efficient, cost-effective system that will be accepted and implemented in low-income housing.

Familial Hirschsprung's disease and type D brachydactyly: a report of four affected males in two generations.

Hirschsprung's disease usually occurs as an isolated malformation as a result of multifactorial causation. A family in which four males (two brothers and two maternal uncles) had Hirschsprung's disease and absence or hypoplasia of the nails and distal phalanges of the great toe and thumb (type D brachydactyly) is described. Hand abnormalities were not present in any other family members, and the obligate heterozygous females were without gastrointestinal problems. The pattern of inheritance was consistent with X-linked recessive inheritance; however, autosomal dominant inheritance with incomplete penetrance in females or multifactorial causation could not be completely excluded.

Reoperation on prosthetic heart values. Patient-specific estimates of in-hospital events.

Reoperation on prosthetic heart valves is increasingly under consideration for both clinical and prophylactic indications. To determine the correlates of hospital events, including in-hospital mortality, new persisting neurologic deficit, and length of postoperative stay, a three-institution study of 2246 consecutive prosthetic valve reoperations performed on 1984 patients between 1963 and 1992 was undertaken. The combined experience ranged from high-risk patients coming moribund to the operating room to an important number of well individuals undergoing prophylactic reoperations on potentially failing valves. The risk-unadjusted hospital mortality was 10.8%, neurologic deficit at hospital discharge 1.1%, and length of stay 10 days (median). Multivariably determined correlates of outcome included age at reoperation, degree, severity, and acuity of impairment of cardiac function, extensiveness of valvular heart disease, coexisting morbid conditions, number of previous heart operations, and concomitant procedures. The risk-adjusted hospital mortality for the first elective reoperation in a good-risk patient was 1.3% (90% confidence limits 0.3% to 4.4%), neurologic deficit 0.3% (90% confidence limits 0.02% to 1.8%), and length of postoperative stay 7 days (90% confidence limits 4 to 13), emphasizing the wide variance in outcome events. Equations were developed to permit wide application of the results of the study for quantitatively estimating the risk of outcome events based on individual preoperative patient characteristics. These estimates should be useful for informed patient consent, considerations of prophylactic valve replacement, and cost and resource use.

In vivo accuracy of two radiographic systems in the detection of Björk-Shiley convexo-concave heart valve outlet strut single leg separations.

OBJECTIVE: Modified cineradiographic systems have been used clinically to detect partially broken outlet struts in normally functioning Björk-Shiley convexo-concave heart valves. Almost all such valves were explanted, presuming that full failure would likely follow. Inasmuch as the clinical setting only rarely permits examination of normally rated valves, the accuracy of radiographic detection cannot be clinically defined. This study uses the clinical radiographic technique in sheep implanted with known-status convexo-concave valves, comparing its accuracy and that of a newly developed, geometric image magnification radiography system. METHODS: Twenty-one sheep with mitral convexo-concave valves were studied on both systems. Five were used for extensive training. When operators were expert with both systems, images of four intact valves and 12 valves with outlet strut single leg separations, along with a seventeenth single leg separation valve used for calibration, were integrated into 112 image sets organized into a balanced incomplete block design for evaluation by eight trained, blinded reviewers. RESULTS: Cineradiography sensitivity was 24% versus 31% for direct image magnification. The odds ratio for detection of single leg separation by direct image magnification versus cineradiography was 2.0 (95% confidence interval, 0.76 to 5.9; p = 0.13). Cineradiography specificity was 93% versus 90% for direct image magnification. Sensitivity and specificity varied markedly by reviewer, with sensitivity ranging from 8% to 55% and specificity from 51% to 100% for the combined technologies. CONCLUSIONS: The data support the need for more intensive training for convexo-concave valve imaging and further investigation of unconventional radiographic technologies. Clinical cineradiography of convexo-concave valves may detect as little as 25% of valves having a single leg separation, underestimating the prevalence of single leg separations and thereby implying more rapid progression to full fracture than is actually the case.

Chylous ascites in infants and children.

Chylous ascites in infants and children has been the subject of 35 articles in the English language literature during the past 30 years. Analysis of the cases of 58 patients reveals that chylous ascites has been reported twice as frequently in infants as in older children, but that the clinical presentations, essentials of diagnosis, treatment alternatives, and mortality rates have been otherwise remarkably similar. Two thirds of patients treated without operation were cured, half of them within the first month of therapy. Even though the documented experience with total parenteral nutrition in infants and children with chylous ascites is remarkably scant, parenteral nutritional support appears to have decreased the hazard of medical therapy by maintaining an adequate nutritional intake while eliminating obligate losses consequent to repeated paracentesis. Patients in whom chylous ascites recurs, after resumption of a regular diet, should undergo surgical exploration, according to a defined strategy that includes visualization of the retroperitoneal origin of the superior mesenteric artery.

Surgical complications of neuroblastoma resection.

Locally advanced neuroblastomas in infants and very young children often require intricate dissection to separate the tumors from the anatomic structures that they have enmeshed. The rationale for these procedures is based mainly on the premise that near-total resection is almost as effective as total extirpation, given favorable circumstances of age and stage. The principal reason for not undertaking or aborting such resections has been to avoid the fallacy of intentionally sacrificing vital structures, causing serious disability, in circumstances in which cure is either impossible or equally likely to accrue from a lesser procedure. This report describes five surgical mishaps, two of which resulted in postoperative deaths. The potential for these complications was greatest during resection of locally advanced tumors in small babies. We suspect that this hazard is more prevalent than its scarcity in the literature would suggest and that potential for unintended injury should be a prominent factor in the decision to proceed or desist with resection of a large neuroblastoma.

Changes in respiratory function following small bowel bypass for obesity.

Spirometry and arterial blood gases were determined before operation and at approximately 6-month postoperative intervals in 11 patients weighing 137 +/- 22 kg (234% +/- 41% of actuarial ideal weight), who underwent a small bowel bypass which left 30 cm of proximal jejunum and 20 cm of distal ileum in end-to-end continuity. The average follow-up period was 20 months, during which time mean weight loss was 31% +/- 8%. Preoperative spirometry was normal, but the patients were significantly hypoxic (PaO2 = 75.3 +/- 8.5 mm Hg) as compared with an age-matched norm (P less than 0.001). PaCO2 and pH were normal. After operation changes in forced vital capacity (FVC) showed a significant linear correlation with the percentage of body weight lost: y = 1.03 x -29 (r = 0.75, P less than 0.001). Because of a significant (P less than 0.001) decrease in FVC, identified in seven patients, during the early period of rapid weight loss, the x intercept occurred at a weight loss of 27.5%. Additional weight reduction was attended by progressive improvement in FVC to values slightly higher, but not significantly different, than preoperative measurements. Forced expiratory volume at 1 second (FEV) varied in accord with FVC. Hypoxia persisted after operation and was unaffected by the amount of weight lost. The results suggest that loss of lean body mass, during the initial phase of rapid weight loss after intestinal bypass, may be detrimental to respiratory function, until a sufficient excess of fat also has been lost to achieve net benefit.

Assessment of an implantable ileostomy sphincter.

A totally implanted, intermittently inflatable, silicone rubber cuff, reservoir, and control mechanism were evaluated for use as an artificial sphincter in 18 female beagle dogs that had undergone ileostomy. The dogs were divided into daily 8-hour occlusion, test, and always open, control, groups. Animals were evaluated daily for continence and peristomal irritation. Quantitative aerobic and anaerobic cultures, measurements of ileal accommodation, net fluxes of H2O, Na, K, and taurocholate, fecal fat loss, and urinary excretion of oral 58Co X B12 plus mucosal suction biopsies were done at 4, 12, 24, and 36 weeks. Eight hours of daily occlusion caused dependable continence without causing damage to the underlying or upstream mucosa and significantly reduced the incidence of peristomal erosion (6.8 +/- 0.8 days/dog-days X 100 versus 50.7 +/- 7 days/dog-days X 100 [+/- SEM] [p less than 0.001]). Occlusion also promoted anaerobic bacterial growth (9.00 +/- 0.41 logs versus 6.70 +/- 0.58 logs [p less than 0.001]). Test animals showed significant capacitance accommodation of the terminal ileum without incurring defects in ileal absorptive or secretory function. Gangrenous herniation of small bowel through an aperture formed by an intestinal loop adhering to the capsule surrounding the cuff, device failure, and fibrotic obstruction occurred sporadically as late as 29 weeks after implantation. The artifical sphincter was effective and was physiologically well tolerated, but its specific liabilities require further address.

Selectivity of the distal splenorenal shunt.

The distal splenorenal shunt is less likely to provoke encephalopathy than conventional shunting procedures, and it may offer a survival advantage for certain cirrhotic individuals, presumably because of its selective nature. This study suggests that the distal splenorenal shunt, even with exceptional efforts to achieve portomesenteric-gastrosplenic (PM-GS) disconnection, is not nearly as selective as it originally was assumed to be. In 11 patients intraoperative pressure determinations showed a significant decrease in portal pressure after end-to-side distal splenorenal anastomosis and no restoration of portal pressure after PM-GS disconnection. Measurements of flow through the shunt were comparable to those reported for portacaval shunts, and shunt flow was not decreased significantly by PM-GS disconnection. Postoperative angiography showed some PM-GS collateral in 17 of 18 patients, and later angiographic studies showed a tendency for progressive collateral development and consequent loss of hepatopetal portal perfusion. The advantages of the distal splenorenal shunt must accrue from gradual, as opposed to abrupt, portal deprivation, rather than from lasting selectivity.

Axillary, subclavian, and brachiocephalic vein obstruction.

The consequences of occlusion of a major upper extremity vein were evaluated in eight patients with effort thrombosis, ten with thrombosis secondary to intimal injury, six with extrinsic compression, and one hypercoagulable patient, all of whom were followed for an average of 4 years. Twenty-two patients had venography, which confirmed the diagnosis but often failed to define the proximal extent of obstruction. Thirteen patients had noninvasive hemodynamic studies which did not corroborate chronic morbidity, but which were valuable in assessing the effect os specific therapy. Twelve patients were treated with anticoagulants, and six had operative removal or bypass of the obstruction. Three patients had pulmonary emboli; two embolized while on anticoagulants and both died. Swelling, pain, prominent veins, and easy fatigability of the affected extremity were the late sequelae of occlusion. Chronic morbidity was more dependent on etiology than on initial treatment. Thrombosis secondary to intimal injury caused no persistent symptoms, whether treated with anticoagulants or not. Effort thrombosis was intermediate: three fourths complained that their affected arm tired easily and half had prominent veins or persistent swelling. All of those with obstruction secondary to extrinsic compression had easy fatigability. The majority also had concomitant swelling, pain, and prominent collaterals. Operative treatment produced objective improvement in venous outflow but often was unsuccessful in relieving symptoms, particularly in patients with obstruction from extrinsic compression.

Carotid arterial trauma.

The English-language literature, from 1952 to 1979, was surveyed for all papers concerned with vascular trauma penetrating wounds of the neck, or carotid injuries in particular, and all valid, first-hand, adequately detailed cases of carotid arterial trauma were abstracted. The valid, first-hand, adequately detailed cases of carotid arterial trauma were abstracted. The current status of all our own hospital survivors who had been treated for carotid artery injuries was also established to add needed longitudinal perspective. In all, 722 cases were available for analysis. The mean age was 28 years, and the overall mortality rate was 21%. One hundred and eighty-six patients presented with severe neurological deficits. If they underwent arterial repair, 34% were better; if they had a carotid ligated, or were not treated surgically, only 14% improved (P = 0.01). Shock or coma, independently, were significantly ominous (P less than 0.001), but there was no evidence to support coma as a contraindication to restoring arterial continuity. Similarly, in the patients with preoperative neurological deficits, no data could be found to substantiate the contention that prompt arterial repair would yield better results than delayed repair. Follow-up status at 1 year was available for only 40 cases from the results than delayed repair. Follow-up status at 1 year was available for only 40 cases from the entire literature. Assessment of our own patients, at a mean of 4.6 years after injury, uncovered multiple, persistent neurological defects, one stenotic arterial repair, two aneurysms, and an arteriovenous fistula.

Liver regeneration after portacaval transportation in rats.

General recognition of the presence of a specific hepatotrophic factor in portal blood that is necessary for liver regeneration was delayed by two major problems. First, there was a long period of confusion regarding liver atrophy, liver hypertrophy, and cellular hyperplasia. Second, because only exposure to other liver tissue destroys the hepatotrophic activity, all of the studies that were based on bypassing the portal blood into the systemic circulation merely diluted the active substance, which still was available to the hepatocytes by recirculation through the hepatic artery. These problems have been resolved by the development of more sophisticated methods by which to assay liver regeneration and by the introduction of the double liver model to study regeneration. During the time when liver weight alone was used to assess regeneration, the regenerative capacity of the liver was reported to be much greater after portacaval transposition than after end-to-side portacaval shunt, a finding that is inconsistent with current knowledge of the hepatotrophic portal blood factor. To re-evaluate the effect on liver regeneration of providing a compensatory systemic venous inflow after complete portal diversion, 40 partially hepatectomized inbred rats which had previously undergone either a sham operation and end-to-side portacaval shunt or a portacaval transposition were compared on the basis of six separate criteria of regeneration. All of the livers actively regenerated and no significant advantage of providing a substitute systemic venous inflow to the liver could be detected by any of the criteria.

Three spectra of laparoscopic entry access injuries.

BACKGROUND: Procedure-based surveys oflaparoscopic entry access injuries show a reassuringly low incidence, varying from 5 per 10,000 to 3 per 1,000, and, consequently, can provide only limited specific injury data. The current study uses existing injury-based reporting systems to access a uniquely large number of entry injuries to define the nature and outcomes of such events. STUDY DESIGN: Claims arising from US and non-US entry access injuries, between 1980 and 1999, reported to the Physicians Insurers Association of America by their member and affiliate companies and entry-injury medical device reports to the US FDA, from 1995 through October 1997, were analyzed to determine operative procedures, physician specialties, entry devices, and techniques associated with specific injuries. Individual injuries were analyzed for their relative incidence and potential to cause disability and death. RESULTS: Five hundred ninety-four structures or organs were injured in 506 patients, resulting in 65 deaths (13%). General surgical procedures made up at least 67% of combined medical device reports and US Physicians Insurers Association of America cases, and gynecologic procedures accounted for 63% of non-US claims. Bowel and retroperitoneal vascular injuries comprised 76% of all injuries incurred in the process of establishing a primary port. Nearly 50% of both small and large bowel injuries were unrecognized for 24 hours or longer. Delayed recognition, along with age greater than 59 years and major visceral vascular injuries, were each independent significant predictors of death. CONCLUSIONS: No entry technique or device is absolutely safe. Avoidance of entry injuries depends on patient-specific anatomic orientation and control of entry axial force. Certain entry devices can be facilitating in controlling axial force. Overall, this large aggregate of entry access injuries shows them to be more serious and, along with other data, implies that they might be more common than reported in procedure-based studies.

Litigious consequences of open and laparoscopic biliary surgical mishaps.

Three hundred six injuries or complications coincident to 296 laparoscopic cholecystectomies were analyzed for the nature and extent of injuries and litigious outcomes that followed. The data were drawn from 31 member companies of the Physician Insurers Association of America, a trade association that initiated the study. The outcomes were compared to 261 contemporaneous open cholecystectomy claims. Biliary tract injuries were the most common, accounting for almost two thirds of all injuries. The spectrum of cases, originally selected for indemnity potential, reflected relative incidences in the medical literature. Laparoscopic injuries were significantly more severe, more likely to result in indemnity, and more apt to involve higher mean +/- standard deviation dollar values (160 dollars +/- 154 x 10(3)) to surviving claimants than injuries resulting from open procedures (106 dollars +/- 122 x 10(3), P = 0.01). Injury recognition at the time of the original procedure had no discernible mitigating effect because 80% of recognized injuries required an additional operative procedure. Risk-aversive behavior should include paying particular attention to placement of the first port, more liberal use of the Hasson technique, placement of all other ports under direct vision, elimination of intraoperative anatomic uncertainty, programmed inspection of the abdomen before withdrawing the laparoscope, and acquiring sufficient knowledge of electrosurgical principles to ensure the safe use of this potentially dangerous modality.

Mortality and morbidity of pancreatic injury.

Pancreatic trauma, regardless of etiology, has been consistently associated with a mortality of 20 percent and enormous morbidity. Twenty-five pancreatic injuries, including four solitary wounds of the pancreas, were analyzed to determine why pancreatic trauma should have such an adverse prognosis. Eleven patients were victims of blunt trauma and fourteen sustained gunshot wounds. There were no stab wounds. The important determinants of mortality were associated injuries to major vessels, wounds of the head of the gland, and failure to adequately control leaking exocrine secretion. All four deaths were directly related to massive hemorrhage; in two instances leakage of pancreatic juice was also implicated. With the exception of benign solitary blunt wounds of the pancreas to the body of the gland immediately ventral to the spinal column, an injury of the pancreas is evidence that the abdomen has been subjected to severe trauma, which predisposes the patient to a high mortality and morbidity. The pancreatic injury, interacting with other abdominal injuries, is likely to be a cause of significant mortality and to result in complications that will prolong the patient's hospitalization.