Síntomas gastrointestinales, disfunción respiratoria, hepática y renal, principales factores asociados a letalidad por rickettsiosis trasmitida por garrapatas en Mexicali, Baja California, México / Gastrointestinal symptoms, respiratory, hepatic and renal dysfunction, main factors associated with lethality due to tickborne rickettsiosis in Mexicali, Baja California, Mexico

INTRODUCCIÓN: La rickettsiosis, enfermedad potencialmente mortal, es trasmitida por vectores como Rhipicephalus sanguineus, Dermacentor variabilis y D. andersonii, reservorios de Rickettsia rickettsii. En Baja California, México, es endémica, multifactorial, tiene alta letalidad, sus manifestaciones clínicas inespecíficas y ataque multisistémico dificultan el diagnóstico y tratamiento oportuno. OBJETIVO: Identificar los factores de riesgo asociados a la letalidad por rickettsiosis trasmitida por garrapatas en Mexicali, Baja California. PACIENTES Y MÉTODOS : Estudio observacional, analítico, transversal, retrospectivo, de 40 registros de pacientes con diagnóstico confirmado de rickettsiosis, periodo 2014 a 2018. Variables analizadas: sociodemográficas, clínicas, laboratorio clínico, evolución y desenlace. Se reportan frecuencias y medidas de asociación. RESULTADOS: 24 defunciones y 16 vivos. Más de 90% tuvo contacto conocido con garrapatas. Afectó en su mayoría a < 45 años en ambos grupos. La evolución antes del ingreso fue similar y la estancia hospitalaria fue mayor en los pacientes vivos (3,2 ± 4.7 vs 10,62 ± 7,6 p = 0,0002). Fiebre, cefalea, mialgias fueron predominantes. Datos asociados con letalidad: disfunción respiratoria (OR 38,33 IC95% 4,06-361,3 p < 0,0001), creatinina elevada (OR 15,4 IC95% 3,08-76,77 p < 0,0003), retardo del llenado capilar (OR 13,0 IC95% 2,73-61,78 p = 0,0005), dolor abdominal (OR 8,33, IC95% 1,90-36,44 p = 0,0029), AST (OR 7,5, IC95% 1,69-33,27 p = 0,005). CONCLUSIÓN: Esta enfermedad requiere de identificación temprana de factores que se asocian con letalidad para un tratamiento oportuno y adecuado.

BACKGROUND: Rickettsiosis, a potentially fatal disease, is transmitted by vectors such as Rhipicephalus sanguineus, Dermacentor variabilis and D. andersonii, reservoirs of Rickettsia rickettsii. In Baja California, Mexico, it is endemic, multifactorial, has high lethality, its nonspecific clinical manifestations and multisystem attack make diagnosis and timely treatment difficult. AIM: Identify the risk factors associated with lethality due to tick-transmitted rickettsiosis in Mexicali, Baja California. METHODS: Observational, analytical, cross-sectional, retrospective study of 40 records of patients with a confirmed diagnosis of rickettsiosis, period 2014 to 2018. Analyzed variables: sociodemographic, clinical, clinical laboratory, evolution and outcome. Frequencies and association measures are reported. RESULTS: 24 patients died and 16 survived. More than 90% had reported contact with ticks. It mostly affected ≤ 45 years in both groups. The evolution before admission was similar, and the hospital stay was longer in patients who lived (3.2 ± 4.7 vs 10.62 ± 7.6 p = 0.0002). Fever, headache, and myalgia are predominant. Data associated with lethality: respiratory dysfunction (OR 38.33 95% CI 4.06-361.3 p < 0.0001), elevated creatinine (OR 15.4 95% CI 3.08-76.77 p < 0.0003), delayed capillary refill (OR 13.0, 95% CI 2.73-61.78 p = 0.0005), abdominal pain (OR 8.33, 95% CI 1.90-36.44 p = 0.0029), AST (OR 7.5, 95% CI 1.69-33.27 p = 0.005). CONCLUSION: This disease requires early identification of factors that are associated with lethality for timely and adequate treatment.

Hospitalisation by tick-borne diseases in the last 10 years in two hospitals in South Spain: analysis of tick exposure data collected in the Emergency Department.

Tick-borne diseases (TBDs) can sometimes cause severe symptoms and lead to hospitalisation, but they often go unnoticed in the Emergency Department (ED). The aim of this study was twofold: (i) to describe the profile of patients hospitalised by TBDs; and (ii) to evaluate the data collected in the medical records from the ED in order to analyse their potential clinical consequences. A total of 84 cases that included all TBD diagnoses registered in the ED records were identified and analysed. These corresponded to all the hospitalisations by TBDs in the last 10 years (2009-2019) in two tertiary hospitals in Granada, Spain. Statistical analyses were made using RStudio. Coinciding with the absence of patient's report of exposure to ticks, 64.3% of TBDs were not suspected in the ED. Intensive care unit admission was required in 8.3% of cases, and the mortality rate was 2.4%. Non-suspected cases showed longer hospital stay (P < 0.001), treatment duration (P = 0.02) and delay in the initiation of antibiotic treatment (P < 0.001). Our findings indicate that symptoms associated with TBDs are highly non-specific. In the absence of explicit information related to potential tick exposure, TBDs are not initially suspected. As a consequence, elective treatment administration is delayed and hospitalisation time is prolonged. In conclusion, our results highlight the importance of addressing potential exposure to ticks during the ED contact with patients presenting with febrile syndrome.

Comorbid infections induce progression of visceral leishmaniasis.

BACKGROUND: Visceral leishmaniasis (VL) is a vector borne zoonotic disease endemic in humans and dogs in Brazil. Due to the increased risk of human infection secondary to the presence of infected dogs, public health measures in Brazil mandate testing and culling of infected dogs. Despite this important relationship between human and canine infection, little is known about what makes the dog reservoir progress to clinical illness, significantly tied to infectiousness to sand flies. Dogs in endemic areas of Brazil are exposed to many tick-borne pathogens, which are likely to alter the immune environment and thus control of L. infantum. RESULTS: A cross-sectional study of 223 dogs from an area of Natal, in the Rio Grande do Norte, Brazil, were studied to determine the association between comorbid tick-borne disease and Leishmania infection in this endemic area. The risk of Leishmania seropositivity was 1.68× greater in dogs with tick-borne disease seropositivity compared to those without (Adjusted RR: 1.68, 95% CI: 1.09-2.61, P = 0.019). A longitudinal study of 214 hunting dogs in the USA was conducted to determine the causal relationship between infection with tick-borne diseases and progression of VL. Hunting dogs were evaluated three times across a full tick season to detect incident infection with tick-borne diseases. A logistic regression model with generalized estimating equations to estimate the parameters was used to determine how exposure to tick-borne disease altered VL progression over these three time points when controlling for other variables. Dogs infected with three or more tick-borne diseases were 11× more likely to be associated with progression to clinical VL than dogs with no tick-borne disease (Adjusted RR: 11.64, 95% CI: 1.22-110.99, P = 0.03). Dogs with exposure to both Leishmania spp. and tick-borne diseases were five times more likely to die during the study period (RR: 4.85, 95% CI: 1.65-14.24, P = 0.0051). CONCLUSIONS: Comorbid tick-borne diseases dramatically increased the likelihood that a dog had clinical L. infantum infection, making them more likely to transmit infection to sand flies and people. As an important consequence, reduction of tick-borne disease exposure through topical or oral insecticides may be an important way to reduce progression and transmissibility of Leishmania infection from the canine reservoir to people.

Confirming Rickettsia rickettsii as the etiological agent of lethal spotted fever group rickettsiosis in human patients from Espírito Santo state, Brazil.

Although Espírito Santo state is considered an endemic area for Brazilian spotted fever (BSF) with related lethal cases, it also constitutes the only state of southeastern Brazil that currently lacks a specific confirmation of the specific rickettsial agent. In an attempt to a species level confirmation of the etiological agent of fatal rickettsiosis cases in Espírito Santo state, in this study we tested human sera obtained between 2015 to 2017 by means of qPCR and subsequent conventional PCR protocols targeting gltA (citrate synthase) and ompA (190-kDA outer membrane protein) rickettsial genes. All samples were found to contain rickettsial DNA through the citrate synthase qPCR protocol. By conventional PCR, rickettsial gltA and ompA specific DNA fragments were detected in 25% (one sample) and 50% (2 samples) of the screened sera, respectively. Obtained consensuses for each gene partial sequences were 100% identical to Rickettsia rickettsii gltA and ompA genes. The present study confirms for the first time R. rickettsii as the etiological agent of a lethal spotted fever group rickettsiosis in human patients from Espírito Santo state.

Severe Fever with Thrombocytopenia Syndrome in South Korea, 2013-2015.

BACKGROUND: Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease that was recently identified in China, South Korea and Japan. The objective of the study was to evaluate the epidemiologic and clinical characteristics of SFTS in South Korea. METHODS/PRINCIPAL FINDINGS: SFTS is a reportable disease in South Korea. We included all SFTS cases reported to the Korea Centers for Disease Control and Prevention (KCDC) from January 2013 to December 2015. Clinical information was gathered by reviewing medical records, and epidemiologic characteristics were analyzed using both KCDC surveillance data and patient medical records. Risk factors for mortality in patients with SFTS were assessed. A total of 172 SFTS cases were reported during the study period. SFTS occurred throughout the country, except in urban areas. Hilly areas in the eastern and southeastern regions and Jeju island (incidence, 1.26 cases /105 person-years) were the main endemic areas. The yearly incidence increased from 36 cases in 2013 to 81 cases in 2015. Most cases occurred from May to October. The overall case fatality ratio was 32.6%. The clinical progression was similar to the 3 phases reported in China: fever, multi-organ dysfunction, and convalescence. Confusion, elevated C-reactive protein, and prolonged activated partial thromboplastin times were associated with mortality in patients with SFTS. Two outbreaks of nosocomial SFTS transmission were observed. CONCLUSIONS: SFTS is an endemic disease in South Korea, with a nationwide distribution and a high case-fatality ratio. Confusion, elevated levels of C-reactive protein, and prolonged activated partial thromboplastin times were associated with mortality in patients with SFTS.

Crimean-Congo haemorrhagic fever in travellers: A systematic review.

BACKGROUND: The recent Ebola epidemic has increased public awareness of the risk of travel associated viral haemorrhagic fever (VHF). International preparedness to manage imported cases Ebola virus infection was inadequate, highlighted by cases of nosocomial transmission. Crimean-Congo haemorrhagic fever (CCHF) is a re-emerging tick-borne VHF centred in the Eurasian region, affecting a large geographical area and with human-to-human transmission reported, especially in the healthcare setting. OBJECTIVES: To systematically review the characteristics of travel associated Crimean-Congo haemorrhagic fever. METHODS: A systematic review of travel-associated cases of CCHF was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement protocol. PubMed, SCOPUS, Science Citation Index (SCI) and ProMED databases were searched for reports published between January 1960 and January 2016. Three independent reviewers selected and reviewed studies and extracted data. RESULTS: 21 cases of travel associated CCHF were identified, of which 12 died (3 outcome unknown) and 4 secondary (nosocomial) infections were reported. Risk occupations or activities for CCHF infection were reported in 8/12 cases when data were available. Travel from Asia to Asia occurred in 9 cases, Africa to Africa occurred in 5 cases, Africa to Europe in 3 cases, Asia to Europe in 2 cases and Europe to Europe in 2 cases. CONCLUSION: CCHF related to travel is rare, is generally associated with at risk activities/occupation and is frequently fatal. Key to early diagnosis and prevention of nosocomial transmission is an understanding of CCHF risk factors and the geographical distribution of CCHF. International travel to CCHF endemic areas is increasing and clinicians and laboratory personnel managing returning travellers should maintain a high index of suspicion.

A longitudinal assessment of the serological response to Theileria parva and other tick-borne parasites from birth to one year in a cohort of indigenous calves in western Kenya.

Tick-borne diseases are a major impediment to improved productivity of livestock in sub-Saharan Africa. Improved control of these diseases would be assisted by detailed epidemiological data. Here we used longitudinal, serological data to determine the patterns of exposure to Theileria parva, Theileria mutans, Babesia bigemina and Anaplasma marginale from 548 indigenous calves in western Kenya. The percentage of calves seropositive for the first three parasites declined from initial high levels due to maternal antibody until week 16, after which the percentage increased until the end of the study. In contrast, the percentage of calves seropositive for T. mutans increased from week 6 and reached a maximal level at week 16. Overall 423 (77%) calves seroconverted to T. parva, 451 (82%) to T. mutans, 195 (36%) to B. bigemina and 275 (50%) to A. marginale. Theileria parva antibody levels were sustained following infection, in contrast to those of the other three haemoparasites. Three times as many calves seroconverted to T. mutans before seroconverting to T. parva. No T. parva antibody response was detected in 25 calves that died of T. parva infection, suggesting that most deaths due to T. parva are the result of acute disease from primary exposure.

Causes of calf mortality in peri-urban area of Nairobi, Kenya.

The study reported data from 507 post-mortem records in the Department of Pathology, Microbiology and Parasitology, Faculty of Veterinary Medicine, University of Nairobi, Kenya. The records were from carcasses obtained from the peri-urban area of Nairobi during a 20-year period between 1990 and 2009. Approximately 80% (393/507) of the calf carcasses had their diagnosis made through post-mortem examination, while the rest (114/507) were inconclusive. Just less than half (48.3%) of the calf carcasses presented had their age specified by the owners compared to 51.7% whose age was not specified. For calf carcasses whose age was specified by the owners, those indicated as more than 3 months were one-and-a-half times as many as those below 3 months old. The proportion of female carcasses (53.8%, 273/507) presented for post-mortem were slightly higher than the male carcasses (46.2%, 234/507). Diseases or conditions of the respiratory system were the most common 17.7% (97/507) while gastrointestinal tract (GIT) was second and affected 16.1% (88/507) of the cases. Another small number, 3.3% (18/507), died from bloat giving the total cases associated with GIT as 19.4% (106/507). Severe calf malnutrition and septicaemia were the third most reported causes of calf mortality in similar proportions at 14.3% (78/507) and 14.4% (79/507), respectively. Other minor causes of calf mortality were tick-borne diseases 8.6% (47/507), helminthiasis and poisoning, 2.9% (16/507) and 1.8% (10/507), respectively.

Systematic review of causes and factors associated with morbidity and mortality on smallholder dairy farms in eastern and southern Africa.

This article presents the first systematic review of the causes and factors associated with morbidity and mortality, on smallholder dairy farms in Eastern and Southern Africa. It was conducted in August 2007. Primary studies on causes of morbidity and mortality on smallholder dairy farms in the region were identified, examined and descriptive information extracted. Electronic (CAB Abstracts, PubMed, ScienceDirect and Web of Science) and non-electronic databases were used to identify and retrieve the primary studies. The retrieval process included all types of study designs with no restriction on the year of publication and language. Mastitis, tick-borne diseases (TBDs), tick infestation and diarrhoea were among the most commonly documented causes of morbidity. TBDs, diarrhoea and trypanosomiasis were among the most commonly documented causes of mortality; however, a substantial number of mortalities with undiagnosed causes were also reported. Factors ranked as most negatively associated with mastitis were residual calf suckling and increased water availability on the farm while use of common udder towel was the factor most positively associated with mastitis. Zero-grazing was ranked as the factor most negatively associated with TBDs while age was most positively associated. More intervention studies are recommended in the region to better identify animal health constraints and their associated risk factors.

Tick bites and skin rashes.

PURPOSE OF REVIEW: Fever and a rash following a tick bite can signify a true medical emergency. Ticks are important vectors of disease worldwide, including Rocky Mountain spotted fever, Lyme disease, and Congo-Crimean hemorrhagic fever. This paper will review the major ticks of medical importance and the diseases they transmit, including important emerging pathogens. RECENT FINDINGS: Rocky Mountain spotted fever continues to be the most lethal tick-borne illness in the United States and is emerging as an important disease in South America. Other important emerging diseases include human anaplasmosis, southern tick associated rash illness, human monocytic ehrlichiosis, and a variety of rickettsial fevers including those caused by Rickettsia parkeri and Rickettsia amblyommii. SUMMARY: Most tick-borne illnesses respond readily to doxycycline therapy. In the case of Rocky Mountain spotted fever, therapy should be started when the disease is suspected and should never be delayed for confirmatory tests. Accurate identification of tick vectors can help establish a diagnosis and can help guide preventive measures to reduce the burden of disease.

A longitudinal study on morbidity and mortality in youngstock smallholder dairy cattle with special reference to tick borne infections in Tanga region, Tanzania.

The incidence and potential determinants of tick borne diseases (TBDs) were estimated in a longitudinal study that was conducted in cohorts of youngstock animals of less than 3 years kept in smallholder dairy farms in Tanga region, Tanzania. A combination of serological tests, blood and lymph node smears were used as diagnostic tests for TBDs during the study. A total number of 549 youngstock were followed for a total of 532.2 animal years from August 1999 to July 2001. Overall morbidity and mortality rates (due to all causes) were 8.26 and 12.0 per 100 animals year at risk, respectively. Of the total deaths, 56% were attributed to TBDs (37.5%-East Coast fever (ECF) and 18%-anaplasmosis). Specific morbidity and mortality rates for ECF were estimated to be 3.57 and 4.51 per 100 animals year risk, respectively, and for anaplasmosis 2.21 and 2.25 per 100 animals year risk, respectively. Analysis of survival times to death indicated that calves < 6 months of age and those out on pasture had higher death rates than older calves and those kept under zero-grazing systems (relative risk [RR] 3.80, P = 0.001 for pasture-grazed calves). There was no mortality or morbidity arising specifically from cowdriosis (heartwater) or babesiosis during the whole period of monitoring. The study revealed that most farms were applying under strength acaricide and using acaricides at irregular intervals. It is concluded that TBDs namely ECF and anaplasmosis are important diseases in this farming system and reducing morbidity and mortality in smallholder dairy farms in Tanga region is an achievable goal. Both farmers and extension services should target at risk calves with the provision of both strict tick control and optimal husbandry management practices.

A longitudinal study of disease incidence and case-fatality risks on small-holder dairy farms in coastal Kenya.

A longitudinal study was carried out in the coastal lowlands coconut-cassava agro-ecological zone of Kaloleni Division, Coast Province, Kenya between June 1990 and December 1991 to estimate disease incidence and cause-specific case-fatality risk in an average of 120 cattle in 26 small-holder dairy herds kept in two grazing-management systems. East Coast fever (ECF) was the predominant disease diagnosed; the mean monthly incidence rate was 2.5 and 6.9% in animals < or = 18 months of age under stall-fed and herded-grazing systems, respectively. In cattle > 18 months of age, the monthly incidence rate was < 1%. The 6-month ECF incidence rate was 20+/-8% (S.E.) in the stall-feeding system compared with 39+/-7% in the herded-grazing systems. There was a gradual increase in antibody prevalence with age to over 90% in cattle over 18 months of age in herded-grazing systems, whilst less than a third of cattle in the stall-feeding systems were sero-positive at any age. Overall accumulated mortality to 18 months of age was estimated to be 56%. Annual mortality in cattle > 18 months averaged 9%. Cattle managed in the herded-grazing system had a 60% higher mortality, although not significantly so, than those fed in stalls. Deaths due to ECF accounted for over two-thirds of the deaths. ECF was then the major disease constraint to small-holder dairy production in the coconut zone of coastal Kenya. Clinical cases occur the whole year round (especially in young stock)--despite apparent tick control, and in both herded-grazing and stall-feeding system.

The role of parasitic diseases as causes of mortality in cattle in a high potential area of central Kenya: a quantitative analysis.

Postmortem records of cattle brought to the Veterinary School in Kabete near Nairobi were examined for a period of 15 years (1984-1998, inclusive) in order to establish the role that parasitic diseases played as causes of death. The cattle were mainly of exotic breeds but a few were crosses or of indigenous breeds. There was a total of 1413 cases of deaths from various diseases of which 177 (13%) were due to parasites. The tick-borne diseases were in high proportions and accounted for 84,7% among the parasitic causes, which represented 10,6% of all the deaths recorded. The main tick-borne disease was East Coast fever (ECF) (65%) followed by heartwater (10,2%), babesiosis (5,1%) and anaplasmosis (4,5%). Hydatidosis was responsible for 7,3% of deaths from parasitic causes. Deaths from ECF were recorded in all the 15 years and in high proportions compared to those due to heartwater (8/15), babesiosis (7/15) and anaplasmosis 5/15). Over the period under consideration, no decline was noted among various disease conditions despite advances made in controlling tick vectors and in the treatment of various parasitic conditions. The area covered by this study has the advantage of having several veterinary-related institutions close by. Hence knowledge and awareness about livestock diseases is relatively high compared to other parts of the country. It is therefore challenging to the Veterinary Department to examine the service delivery systems and other factors that may contribute to the persistent presence of these fatal parasitic conditions of cattle.

Anaplasmosis control and diagnosis in South Africa.

Anaplasmosis is widespread in South Africa with more than 99% of the total cattle population at risk. Five tick species have been experimentally shown to be capable of transmitting Anaplasma in South Africa. Mechanical transmission through blood contaminated instruments and biting flies also occurs. Vaccination against Anaplasma marginale by administration of an Anaplasma centrale live-blood vaccine has been practiced in this country since 1912. Although generally a mild pathogen, Anaplasma centrale can cause severe clinical reactions following vaccination and also does not afford complete protection against all A. marginale isolates. Anaplasmosis vaccine is routinely available in a deep-frozen form and approximately 220,000 doses of vaccine are sold per annum. Microscopic examination of stained thin blood smears is still the most reliable and cost effective method of confirming a clinical diagnosis of anaplasmosis. Several diagnostic tests, such as the complement fixation tests, card agglutination test, and enzyme-linked immunosorbent assay (ELISA) have been developed to identify carrier cattle. A competitive inhibition ELISA test, based on antibody binding to a recombinant MSP-5 protein conserved among Anaplasma species, is routinely used at this laboratory.

Ixodid ticks (Acari: Ixodidae) and livestock production: effect of varying acaricide treatments on ticks and productivity in east coast fever-immunized weaner and dairy cattle.

In a pilot trial to evaluate cost-effective methods of acaricide application, east coast fever-immunized weaner and dairy cattle were subjected to varying tick control regimens. All experimental cattle were maintained under the same extensive system of management. Their monthly tick load, packed cell volumes, incidence of blood protozoans, weight changes, and daily milk production were noted. Apart from Rhipicephalus appendiculatus Neumann, other tick species found in the study site were R. pulchellus Gerstacker, Amblyomma gemma Donitz, Boophilus decoloratus Koch, and A. variegatum F. The control group under a weekly regimen of dipping had fewer ticks than each of the other groups for both weaner and dairy cattle. However, the percentage of increase in weight of the weaner cattle was least for the control group. The milk production of none of the groups was significantly different from that of the control group, although profit per animal for groups maintained under a monthly or six-weekly regimen of acaricide use was highest. The age of the experimental dairy cattle was found not to have any effect on their milk production. It is suggested that with successful immunization against east coast fever, both dairy and weaner cattle may be subjected to reduced dipping or spraying, the level of relaxation being dependent on the tick challenge. However, similar studies should be carried out in as many agroecological zones as possible using different breeds of cattle. Information on the level of acaricide residues in livestock products from different farming systems should also be generated. Only then can a definitive recommendation for a change from the present national intensive dipping policy be made.